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Understanding U-Codes: Vehicle Communication Network Diagnostics
U-Codes (Diagnostic Trouble Codes starting with “U“) are related to vehicle communication network issues, primarily affecting CAN (Controller Area Network) buses and other data-sharing systems. These codes indicate problems with how different modules (ECU, TCM, BCM, etc.) communicate, which can impact everything from engine performance to safety systems.
Why U-Codes Matter
-
- Critical for modern vehicles – Most systems rely on network communication.
- Affect multiple functions – From ABS and airbags to infotainment and transmission control.
- Diagnostic priority – Some U-Codes can disable entire systems (e.g., U0073/U0074 = Complete bus failure).
Severity Guide
🔴 Critical: Complete communication failure (vehicle may not start/operate)
🟠 High: Major network issues (systems may not function properly)
🟡 Medium: Partial communication problems (reduced functionality)
⚪ Reserved: No immediate action needed
Common Causes Across U-Codes
-
- Damaged wiring harness
- Corroded connectors
- Faulty control modules
- Short circuits (power/ground)
- Improper termination resistors
- Voltage spikes/electrical interference
U-Code Diagnostic Trouble Codes (DTCs) Reference Table
📚 U0001 – U0099
(Color Key: 🔴 Critical | 🟠 High | 🟡 Medium | ⚪ Reserved/Info)
| DTC Code | Severity | Description | Possible Causes |
|---|---|---|---|
| U0000 | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0001 | 🔴 Critical | High Speed CAN Communication Bus | CAN bus wiring fault, module failure, short to power/ground |
| U0002 | 🔴 Critical | High Speed CAN Communication Bus Performance | Bus signal degradation, termination resistor issue |
| U0003 | 🔴 Critical | High Speed CAN Bus (+) Open | Broken CAN+ wire, poor connection |
| U0004 | 🟠 High | High Speed CAN Bus (+) Low | Short to ground, weak signal |
| U0005 | 🟠 High | High Speed CAN Bus (+) High | Short to power, voltage spike |
| U0006 | 🔴 Critical | High Speed CAN Bus (-) Open | Broken CAN- wire, disconnected connector |
| U0007 | 🟠 High | High Speed CAN Bus (-) Low | Short to ground, signal interference |
| U0008 | 🟠 High | High Speed CAN Bus (-) High | Short to power, wiring damage |
| U0009 | 🔴 Critical | High Speed CAN Bus (-) Shorted to Bus (+) | CAN wires pinched together, harness damage |
| U000A-U000F | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0010 | 🟠 High | Medium Speed CAN Communication Bus | Faulty module, wiring issue |
| U0011 | 🟠 High | Medium Speed CAN Bus Performance | Signal interference, resistor fault |
| U0012 | 🟠 High | Medium Speed CAN Bus (+) Open | Broken wire, corroded connector |
| U0013 | 🟡 Medium | Medium Speed CAN Bus (+) Low | Partial short to ground |
| U0014 | 🟡 Medium | Medium Speed CAN Bus (+) High | Intermittent short to power |
| U0015 | 🟠 High | Medium Speed CAN Bus (-) Open | Disconnected wire |
| U0016 | 🟡 Medium | Medium Speed CAN Bus (-) Low | Grounding issue |
| U0017 | 🟡 Medium | Medium Speed CAN Bus (-) High | Voltage leak |
| U0018 | 🟠 High | Medium Speed CAN Bus (-) Shorted to Bus (+) | Harness damage |
| U0019 | 🟡 Medium | Low Speed CAN Communication Bus | Faulty body control module |
| U001A-U001F | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0020 | 🟡 Medium | Low Speed CAN Bus Performance | Poor signal quality |
| U0021 | 🟡 Medium | Low Speed CAN Bus (+) Open | Broken wire |
| U0022 | 🟡 Medium | Low Speed CAN Bus (+) Low | Short to ground |
| U0023 | 🟡 Medium | Low Speed CAN Bus (+) High | Short to power |
| U0024 | 🟡 Medium | Low Speed CAN Bus (-) Open | Disconnected wire |
| U0025 | 🟡 Medium | Low Speed CAN Bus (-) Low | Grounding issue |
| U0026 | 🟡 Medium | Low Speed CAN Bus (-) High | Voltage leak |
| U0027 | 🟠 High | Low Speed CAN Bus (-) Shorted to Bus (+) | Pinched wires |
| U0028 | 🟠 High | Vehicle Communication Bus A | Network communication failure |
| U0029 | 🟠 High | Vehicle Communication Bus A Performance | Signal integrity issue |
| U002A-U002F | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0030 | 🟠 High | Vehicle Communication Bus A (+) Open | Broken wire |
| U0031 | 🟡 Medium | Vehicle Communication Bus A (+) Low | Partial short |
| U0032 | 🟡 Medium | Vehicle Communication Bus A (+) High | Voltage spike |
| U0033 | 🟠 High | Vehicle Communication Bus A (-) Open | Disconnected wire |
| U0034 | 🟡 Medium | Vehicle Communication Bus A (-) Low | Grounding issue |
| U0035 | 🟡 Medium | Vehicle Communication Bus A (-) High | Short to power |
| U0036 | 🔴 Critical | Vehicle Communication Bus A (-) Shorted to Bus A (+) | Harness damage |
| U0073 | 🔴 Critical | Control Module Communication Bus A Off | Complete bus failure, module shutdown |
| U0074 | 🔴 Critical | Control Module Communication Bus B Off | Complete bus failure, module shutdown |
📚 U0100 – U0199
| DTC Code | Severity | Description | Possible Causes |
|---|---|---|---|
| U0100 | 🔴 Critical | Lost Communication With ECM/PCM “A” | CAN bus fault, wiring harness issue, ECM/PCM failure |
| U0101 | 🔴 Critical | Lost Communication with TCM | CAN bus disruption, TCM power/ground issue, module failure |
| U0102 | 🟠 High | Lost Communication with Transfer Case Control Module | Wiring fault, connector issue, module failure |
| U0103 | 🟠 High | Lost Communication With Gear Shift Module | CAN bus error, shifter module failure, wiring issue |
| U0104 | 🟡 Medium | Lost Communication With Cruise Control Module | CAN bus fault, cruise control module issue |
| U0105 | 🔴 Critical | Lost Communication With Fuel Injector Control Module | Wiring harness damage, injector control module failure |
| U0106 | 🟠 High | Lost Communication With Glow Plug Control Module | Wiring issue, module failure (diesel engines) |
| U0107 | 🔴 Critical | Lost Communication With Throttle Actuator Control Module | Throttle system failure, wiring issue, safety risk |
| U0108 | 🟠 High | Lost Communication With Alternative Fuel Control Module | Alternative fuel system fault, wiring issue |
| U0109 | 🔴 Critical | Lost Communication With Fuel Pump Control Module | Fuel delivery system failure, wiring issue |
| U010A | 🟠 High | Lost Communication With EGR Control Module “A” | EGR system fault, wiring or connector issue |
| U010B | 🟠 High | Lost Communication With EGR Control Module “B” | Secondary EGR system fault |
| U010C | 🟠 High | Lost Communication With Turbocharger Control Module “A” | Boost control system failure |
| U010D | 🟠 High | Lost Communication With Turbocharger Control Module “B” | Secondary turbo system issue |
| U010E | 🟠 High | Lost Communication With Reductant Control Module | DEF system fault (diesel vehicles) |
| U010F | 🟡 Medium | Lost Communication With A/C Control Module | Climate control system issue |
| U0110 | 🔴 Critical | Lost Communication With Drive Motor Control Module | EV/hybrid propulsion system failure |
| U0111 | 🔴 Critical | Lost Communication With Battery Energy Control Module “A” | High-voltage battery system fault |
| U0112 | 🔴 Critical | Lost Communication With Battery Energy Control Module “B” | Secondary battery control issue |
| U0113 | 🟠 High | Lost Communication With Emissions Critical Control Information | Emissions system failure |
| U0114 | 🟠 High | Lost Communication With 4WD Clutch Control Module | 4WD system malfunction |
| U0115 | 🔴 Critical | Lost Communication With ECM/PCM “B” | Secondary engine control failure |
| U0121 | 🔴 Critical | Lost Communication With ABS Control Module | Braking system failure, safety risk |
| U0122 | 🔴 Critical | Lost Communication With Vehicle Dynamics Control Module | Stability control system failure |
| U0126 | 🟠 High | Lost Communication With Steering Angle Sensor Module | Steering system fault |
| U0127 | 🟡 Medium | Lost Communication With Tire Pressure Monitor Module | TPMS system failure |
| U0129 | 🔴 Critical | Lost Communication With Brake System Control Module | Brake system failure |
| U0131 | 🟠 High | Lost Communication With Power Steering Control Module | Power steering system issue |
| U0140 | 🟠 High | Lost Communication With Body Control Module | BCM communication failure |
| U0151 | 🔴 Critical | Lost Communication With Restraints Control Module | Airbag/SRS system failure |
| U0155 | 🟠 High | Lost Communication With Instrument Cluster | Dashboard/instrument panel failure |
| U0164 | 🟡 Medium | Lost Communication With HVAC Control Module | Climate control system issue |
| U0167 | 🟠 High | Lost Communication With Immobilizer Control Module | Vehicle security system fault |
| U0180 | 🟡 Medium | Lost Communication With Automatic Lighting Control Module | Lighting system issue |
Note: ISO/SAE reserved codes (e.g., U011E, U012A, etc.) are omitted as they have no defined meaning. This table focuses on the most critical and commonly encountered U-codes. The complete list would include all 200+ U-codes with similar formatting.
Severity Key:
-
- 🔴 Critical: Immediate safety concern or vehicle immobilization likely
- 🟠 High: Major system failure affecting drivability or safety
- 🟡 Medium: Comfort/convenience system failure
- 🔵 Low: Minor system issue (not shown as no U-codes qualify as low severity)
Common Root Causes:
-
- CAN bus communication failure
- Wiring harness damage or connector issues
- Module power/ground circuit problems
- Faulty control module
- Software/configuration issues
📚 U0200 – U0299
| DTC Code | Severity | Description | Possible Causes |
|---|---|---|---|
| U0200 | 🟠 High | Lost Communication With Door Control Module B | Wiring fault, module power issue, CAN bus failure |
| U0201 | 🟠 High | Lost Communication With Door Control Module C | Wiring fault, module power issue, CAN bus failure |
| U0202 | 🟠 High | Lost Communication With Door Control Module D | Wiring fault, module power issue, CAN bus failure |
| U0203 | 🟠 High | Lost Communication With Door Control Module E | Wiring fault, module power issue, CAN bus failure |
| U0204 | 🟠 High | Lost Communication With Door Control Module F | Wiring fault, module power issue, CAN bus failure |
| U0205 | 🟠 High | Lost Communication With Door Control Module G | Wiring fault, module power issue, CAN bus failure |
| U0206 | 🟡 Medium | Lost Communication With Folding Top Control Module | Wiring issue, module failure, CAN bus problem |
| U0207 | 🟡 Medium | Lost Communication With Movable Roof Control Module | Wiring issue, module failure, CAN bus problem |
| U0208 | 🟠 High | Lost Communication With Seat Control Module A | Wiring fault, module power issue, CAN bus failure |
| U0209 | 🟠 High | Lost Communication With Seat Control Module B | Wiring fault, module power issue, CAN bus failure |
| U0210 | 🟠 High | Lost Communication With Seat Control Module C | Wiring fault, module power issue, CAN bus failure |
| U0211 | 🟠 High | Lost Communication With Seat Control Module D | Wiring fault, module power issue, CAN bus failure |
| U0212 | 🔴 Critical | Lost Communication With Steering Column Control Module | Wiring fault, module failure, CAN bus issue |
| U0213 | 🟡 Medium | Lost Communication With Mirror Control Module | Wiring issue, module failure, CAN bus problem |
| U0214 | 🟠 High | Lost Communication With Remote Function Actuation | Wiring fault, module power issue, CAN bus failure |
| U0215 | 🟡 Medium | Lost Communication With Door Switch A | Wiring issue, switch failure, connector problem |
| U0216 | 🟡 Medium | Lost Communication With Door Switch B | Wiring issue, switch failure, connector problem |
| U0217 | 🟡 Medium | Lost Communication With Door Switch C | Wiring issue, switch failure, connector problem |
| U0218 | 🟡 Medium | Lost Communication With Door Switch D | Wiring issue, switch failure, connector problem |
| U0219 | 🟡 Medium | Lost Communication With Door Switch E | Wiring issue, switch failure, connector problem |
| U0220 | 🟡 Medium | Lost Communication With Door Switch F | Wiring issue, switch failure, connector problem |
| U0221 | 🟡 Medium | Lost Communication With Door Switch G | Wiring issue, switch failure, connector problem |
| U0222 | 🟠 High | Lost Communication With Door Window Motor A | Wiring fault, motor failure, module issue |
| U0223 | 🟠 High | Lost Communication With Door Window Motor B | Wiring fault, motor failure, module issue |
| U0224 | 🟠 High | Lost Communication With Door Window Motor C | Wiring fault, motor failure, module issue |
| U0225 | 🟠 High | Lost Communication With Door Window Motor D | Wiring fault, motor failure, module issue |
| U0226 | 🟠 High | Lost Communication With Door Window Motor E | Wiring fault, motor failure, module issue |
| U0227 | 🟠 High | Lost Communication With Door Window Motor F | Wiring fault, motor failure, module issue |
| U0228 | 🟠 High | Lost Communication With Door Window Motor G | Wiring fault, motor failure, module issue |
| U0229 | 🟡 Medium | Lost Communication With Heated Steering Wheel Module | Wiring issue, module failure, CAN bus problem |
| U0230 | 🟠 High | Lost Communication With Rear Gate Module | Wiring fault, module power issue, CAN bus failure |
| U0231 | 🟡 Medium | Lost Communication With Rain Sensing Module | Wiring issue, sensor failure, CAN bus problem |
| U0232 | 🔴 Critical | Lost Communication With Left Side Obstacle Detection Control Module | Wiring fault, module failure, safety system issue |
| U0233 | 🔴 Critical | Lost Communication With Right Side Obstacle Detection Control Module | Wiring fault, module failure, safety system issue |
| U0234 | 🟡 Medium | Lost Communication With Convenience Recall Module | Wiring issue, module failure, CAN bus problem |
| U0235 | 🔴 Critical | Lost Communication With Cruise Control Front Distance Range Sensor | Wiring fault, sensor failure, safety system issue |
| U0236 | 🔴 Critical | Lost Communication With Column Lock Module | Wiring fault, module failure, safety system issue |
| U0237 | 🟡 Medium | Lost Communication With Digital Audio Control Module C | Wiring issue, module failure, CAN bus problem |
| U0238 | 🟡 Medium | Lost Communication With Digital Audio Control Module D | Wiring issue, module failure, CAN bus problem |
| U0239 | 🟠 High | Lost Communication With Entrapment Control Module A | Wiring fault, module power issue, CAN bus failure |
| U0240 | 🟠 High | Lost Communication With Entrapment Control Module B | Wiring fault, module power issue, CAN bus failure |
| U0241 | 🟠 High | Lost Communication With Headlamp Control Module A | Wiring fault, module power issue, CAN bus failure |
| U0242 | 🟠 High | Lost Communication With Headlamp Control Module B | Wiring fault, module power issue, CAN bus failure |
| U0243 | 🟠 High | Lost Communication With Parking Assist Control Module B | Wiring fault, module power issue, CAN bus failure |
| U0244 | 🟡 Medium | Lost Communication With Running Board Control Module A | Wiring issue, module failure, CAN bus problem |
| U0245 | 🟡 Medium | Lost Communication With Entertainment Control Module Front | Wiring issue, module failure, CAN bus problem |
| U0246 | 🟠 High | Lost Communication With Seat Control Module E | Wiring fault, module power issue, CAN bus failure |
| U0247 | 🟠 High | Lost Communication With Seat Control Module F | Wiring fault, module power issue, CAN bus failure |
| U0248 | 🟠 High | Lost Communication With Remote Accessory Module | Wiring fault, module power issue, CAN bus failure |
| U0249 | 🟡 Medium | Lost Communication With Entertainment Control Module Rear B | Wiring issue, module failure, CAN bus problem |
| U0250 | 🔴 Critical | Lost Communication With Impact Classification System Module | Wiring fault, module failure, safety system issue |
| U0251 | 🟡 Medium | Lost Communication With Running Board Control Module B | Wiring issue, module failure, CAN bus problem |
| U0252 | 🟠 High | Lost Communication With Lighting Control Module Rear B | Wiring fault, module power issue, CAN bus failure |
| U0253 | 🟠 High | Lost Communication With Accessory Protocol Interface Module | Wiring fault, module power issue, CAN bus failure |
| U0254 | 🟠 High | Lost Communication With Remote Start Module | Wiring fault, module power issue, CAN bus failure |
| U0255 | 🟠 High | Lost Communication With Front Display Interface Module | Wiring fault, module power issue, CAN bus failure |
| U0256 | 🟠 High | Lost Communication With Front Controls Interface Module A | Wiring fault, module power issue, CAN bus failure |
| U0257 | 🟠 High | Lost Communication With Front Controls/Display Interface Module | Wiring fault, module power issue, CAN bus failure |
| U0258 | 🟡 Medium | Lost Communication With Radio Transceiver | Wiring issue, module failure, CAN bus problem |
| U0260 | 🟠 High | Lost Communication With Seat Control Switch Module A | Wiring fault, module power issue, CAN bus failure |
| U0261 | 🟠 High | Lost Communication With Seat Control Switch Module B | Wiring fault, module power issue, CAN bus failure |
| U0262 | 🟡 Medium | Lost Communication With Audio Amplifier B | Wiring issue, amplifier failure, CAN bus problem |
| U0263 | 🟡 Medium | Lost Communication With Speech Recognition Module | Wiring issue, module failure, CAN bus problem |
| U0264 | 🟠 High | Lost Communication With Camera Module Rear | Wiring fault, camera failure, module issue |
| U0286 | 🟠 High | Lost Communication With Radiator Anti Tamper Device | Wiring fault, module power issue, CAN bus failure |
| U0287 | 🔴 Critical | Lost Communication With Transmission Fluid Pump Module | Wiring fault, pump failure, transmission issue |
| U0288 | 🔴 Critical | Lost Communication With DC to AC Converter Control Module A | Wiring fault, converter failure, power system issue |
| U0289 | 🔴 Critical | Lost Communication With DC to AC Converter Control Module B | Wiring fault, converter failure, power system issue |
| U0291 | 🔴 Critical | Lost Communication With Gear Shift Control Module B | Wiring fault, module failure, transmission issue |
| U0292 | 🔴 Critical | Lost Communication With Drive Motor Control Module B | Wiring fault, module failure, EV system issue |
| U0293 | 🔴 Critical | Lost Communication With Hybrid Powertrain Control Module | Wiring fault, module failure, hybrid system issue |
| U0294 | 🔴 Critical | Lost Communication With Powertrain Control Monitor Module | Wiring fault, module failure, engine control issue |
| U0295 | 🔴 Critical | Lost Communication With AC to AC Converter Control Module | Wiring fault, converter failure, power system issue |
| U0296 | 🔴 Critical | Lost Communication With AC to DC Converter Control Module A | Wiring fault, converter failure, power system issue |
| U0297 | 🔴 Critical | Lost Communication With AC to DC Converter Control Module B | Wiring fault, converter failure, power system issue |
| U0298 | 🔴 Critical | Lost Communication With DC to DC Converter Control Module A | Wiring fault, converter failure, power system issue |
| U0299 | 🔴 Critical | Lost Communication With DC to DC Converter Control Module B | Wiring fault, converter failure, power system issue |
| U029A | 🔴 Critical | Lost Communication With Hybrid Battery Pack Sensor Module | Wiring fault, module failure, battery system issue |
| U029B | 🔴 Critical | Lost Communication With Drive Motor Control Module C | Wiring fault, module failure, EV system issue |
| U029C | 🔴 Critical | Lost Communication With Drive Motor Control Module D | Wiring fault, module failure, EV system issue |
| U029D | 🔴 Critical | Lost Communication With NOX Sensor A | Wiring fault, sensor failure, emissions system issue |
| U029E | 🔴 Critical | Lost Communication With NOX Sensor B | Wiring fault, sensor failure, emissions system issue |
Note: ISO/SAE Reserved codes (U020A-U020F, U021A-U021F, etc.) are not included as they have no defined function.
Severity Color Key:
-
- 🔴 Critical: Safety-critical systems affecting vehicle operation or safety
- 🟠 High: Important comfort/convenience systems that significantly impact functionality
- 🟡 Medium: Secondary systems that may affect convenience features
- 🟢 Low: Minor systems with minimal impact on operation (none in this list)
Common Possible Causes:
-
- Wiring harness damage or loose connections
- Blown fuses or power supply issues
- CAN bus communication failures
- Module software or hardware failures
- Ground connection problems
📚 U0300 – U0399
| DTC Code | Severity | Description | Possible Causes |
|---|---|---|---|
| U0300 | 🟠 High | Internal Control Module Software Incompatibility | Corrupted firmware, incorrect software version, module programming error |
| U0301 | 🟠 High | Software Incompatibility with ECM/PCM | PCM/ECM software mismatch, failed update, configuration error |
| U0302 | 🟠 High | Software Incompatibility with Transmission Control Module | TCM software outdated, incorrect flash, wiring fault |
| U0303 | 🟠 High | Software Incompatibility with Transfer Case Control Module | Transfer case module software mismatch, programming error |
| U0304 | 🟡 Medium | Software Incompatibility with Gear Shift Control Module | Shifter module firmware issue, CAN bus communication problem |
| U0305 | 🟡 Medium | Software Incompatibility with Cruise Control Module | Cruise control software bug, module needs reprogramming |
| U0306 | 🟠 High | Software Incompatibility with Fuel Injector Control Module | Fuel injector module software corruption, wiring fault |
| U0307 | 🟡 Medium | Software Incompatibility with Glow Plug Control Module | Glow plug module firmware outdated, poor connection |
| U0308 | 🟠 High | Software Incompatibility with Throttle Actuator Control Module | Throttle body software mismatch, throttle response issues |
| U0309 | 🟡 Medium | Software Incompatibility with Alternative Fuel Control Module | Alternative fuel system software bug, module needs update |
| U0310 | 🟠 High | Software Incompatibility with Fuel Pump Control Module | Fuel pump module software error, power supply issue |
| U0311 | 🟠 High | Software Incompatibility with Drive Motor Control Module | Hybrid/electric motor control software mismatch |
| U0312 | 🟠 High | Software Incompatibility with Battery Energy Control Module A | Hybrid battery module A software corruption |
| U0313 | 🟠 High | Software Incompatibility with Battery Energy Control Module B | Hybrid battery module B firmware issue |
| U0314 | 🟠 High | Software Incompatibility with 4WD Clutch Control Module | 4WD clutch module software outdated |
| U0315 | 🔴 Critical | Software Incompatibility with ABS Control Module | ABS module software mismatch, safety risk |
| U0316 | 🔴 Critical | Software Incompatibility with Vehicle Dynamics Control Module | Stability control system software error |
| U0317 | 🟠 High | Software Incompatibility with Park Brake Control Module | Electronic parking brake software bug |
| U0318 | 🔴 Critical | Software Incompatibility with Brake System Control Module | Brake system software fault, potential brake failure |
| U0319 | 🟠 High | Software Incompatibility with Steering Effort Control Module | Power steering software mismatch |
| U0320 | 🟠 High | Software Incompatibility with Power Steering Control Module | EPS module firmware issue |
| U0321 | 🟡 Medium | Software Incompatibility with Ride Level Control Module | Air suspension/leveling system software bug |
| U0322 | 🟡 Medium | Software Incompatibility with Body Control Module | BCM firmware outdated, configuration error |
| U0323 | 🟡 Medium | Software Incompatibility with Instrument Panel Control Module | Cluster/dash software mismatch |
| U0324 | 🟡 Medium | Software Incompatibility with HVAC Control Module | Climate control module needs reprogramming |
| U0325 | 🟡 Medium | Software Incompatibility with Auxiliary Heater Control Module | Heater module firmware issue |
| U0326 | 🟠 High | Software Incompatibility with Vehicle Immobilizer Control Module | Immobilizer system software error (may prevent starting) |
| U0327 | 🟠 High | Software Incompatibility with Vehicle Security Control Module | Security system software bug |
| U0328 | 🟠 High | Software Incompatibility with Steering Angle Sensor Module | Steering angle sensor calibration/programming issue |
| U0329 | 🟠 High | Software Incompatibility with Steering Column Control Module | Steering column module firmware mismatch |
| U0330 | 🟡 Medium | Software Incompatibility with Tire Pressure Monitor Module | TPMS module software outdated |
| U0331 | 🟡 Medium | Software Incompatibility with Body Control Module “A” | Secondary BCM software corruption |
Severity Legend
-
- 🔴 Critical: Safety-critical systems (e.g., ABS, brakes, stability control).
- 🟠 High: Major drivability/performance impact (e.g., throttle, fuel, steering).
- 🟡 Medium: Non-critical but may cause warnings/limited functionality (e.g., HVAC, TPMS).
Common Root Causes
-
- Incorrect Software Version: Module flashed with wrong firmware.
- Failed Update: Interrupted programming during a dealer/service update.
- CAN Bus Issues: Communication errors between modules.
- Corrupted Memory: ECU/BCM firmware corruption.
Recommended Actions
-
- Reprogram/reflash the affected module.
- Check for technical service bulletins (TSBs) for software updates.
- Verify CAN bus communication and wiring.
📚 U0400 – U0499
| DTC Code | Severity | Description | Possible Causes |
|---|---|---|---|
| U0400 | 🟠 High | Invalid Data Received (Generic) | CAN bus fault, wiring issue, module configuration error |
| U0401 | 🟠 High | Invalid Data Received From ECM/PCM | Faulty PCM, CAN communication error, wiring short/open |
| U0402 | 🟠 High | Invalid Data Received From Transmission Control Module | TCM failure, CAN bus issue, corrupted data |
| U0403 | 🟠 High | Invalid Data Received From Transfer Case Control Module | Transfer case module fault, wiring problem |
| U0404 | 🟡 Medium | Invalid Data Received From Gear Shift Control Module | Shifter module fault, wiring/connector issue |
| U0405 | 🟡 Medium | Invalid Data Received From Cruise Control Module | Cruise control module failure, CAN signal loss |
| U0406 | 🟠 High | Invalid Data Received From Fuel Injector Control Module | Fuel injector module fault, wiring short |
| U0407 | 🟡 Medium | Invalid Data Received From Glow Plug Control Module | Glow plug module failure, communication error |
| U0408 | 🟠 High | Invalid Data Received From Throttle Actuator Control Module | Throttle actuator fault, CAN bus issue |
| U0409 | 🟡 Medium | Invalid Data Received From Alternative Fuel Control Module | Alternative fuel system fault (e.g., CNG/LPG) |
| U040A | 🔵 Low | Invalid Data Received From A/C Control Module | A/C module communication error, wiring issue |
| U040B | 🟡 Medium | Invalid Data Received From EGR Control Module “A” | EGR valve/sensor fault, CAN signal corruption |
| U040C | 🟡 Medium | Invalid Data Received From EGR Control Module “B” | Secondary EGR system fault |
| U040D | 🟠 High | Invalid Data Received From Turbocharger/Supercharger Control Module “A” | Turbo control module failure, boost pressure sensor issue |
| U040E | 🟠 High | Invalid Data Received From Turbocharger/Supercharger Control Module “B” | Secondary turbo system fault |
| U040F | 🟠 High | Invalid Data Received From Reductant Control Module | DEF/AdBlue system fault, SCR module failure |
| U0410 | 🟠 High | Invalid Data Received From Fuel Pump Control Module | Fuel pump module fault, wiring short/open |
| U0411 | 🟠 High | Invalid Data Received From Drive Motor Control Module | Hybrid/electric motor control fault |
| U0412 | 🟠 High | Invalid Data Received From Battery Energy Control Module A | Hybrid battery module A communication error |
| U0413 | 🟠 High | Invalid Data Received From Battery Energy Control Module B | Hybrid battery module B fault |
| U0414 | 🟡 Medium | Invalid Data Received From 4WD Clutch Control Module | 4WD clutch module failure, wiring issue |
| U0415 | 🔴 Critical | Invalid Data Received From ABS Control Module | ABS module failure, CAN bus fault (safety risk) |
| U0416 | 🟠 High | Invalid Data Received From Vehicle Dynamics Control Module | Stability control system fault |
| U0417 | 🟠 High | Invalid Data Received From Park Brake Control Module | Electronic parking brake fault, wiring issue |
| U0418 | 🔴 Critical | Invalid Data Received From Brake System Control Module | Brake system module failure (safety critical) |
| U0419 | 🟡 Medium | Invalid Data Received From Steering Effort Control Module | Electric power steering fault |
| U041B | 🟡 Medium | Invalid Data Received From Exhaust Gas Sensor Module | O2 sensor/NOx sensor communication error |
| U041C | 🟡 Medium | Invalid Data Received From Rocker Arm Control Module “A” | Variable valve timing fault (e.g., solenoid issue) |
| U041D | 🟡 Medium | Invalid Data Received From Rocker Arm Control Module “B” | Secondary valve control fault |
| U041E | 🟠 High | Invalid Data Received From All-Wheel Drive Control Module | AWD system communication failure |
| U041F | 🔵 Low | ISO/SAE Reserved | Reserved for future use |
| U0420 | 🟠 High | Invalid Data From Power Steering Control Module | Faulty steering module, CAN bus wiring, signal interference |
| U0421 | 🟠 High | Invalid Data From Ride Level Control Module | Air suspension fault, module communication error |
| U0422 | 🟠 High | Invalid Data From Body Control Module (BCM) | BCM failure, wiring short, CAN bus issue |
| U0423 | 🟡 Medium | Invalid Data From Instrument Panel Control Module | Cluster malfunction, loose connector |
| U0424 | 🟡 Medium | Invalid Data From HVAC Control Module | HVAC module fault, wiring issue |
| U0425 | 🟡 Medium | Invalid Data From Auxiliary Heater Control Module | Heater module failure, communication error |
| U0426 | 🟠 High | Invalid Data From Vehicle Immobilizer Control Module | Immobilizer system fault, key recognition issue |
| U0427 | 🟠 High | Invalid Data From Vehicle Security Control Module | Security system malfunction, antenna fault |
| U0428 | 🔴 Critical | Invalid Data From Steering Angle Sensor Module | Faulty sensor, alignment issue, ESP system disabled |
| U0429 | 🟠 High | Invalid Data From Steering Column Control Module | Clock spring failure, wiring damage |
| U0430 | 🟡 Medium | Invalid Data From Tire Pressure Monitor Module | Dead TPM sensor, signal interference |
| U0431 | 🟠 High | Invalid Data From Body Control Module “A” | BCM software glitch, CAN bus fault |
| U0432 | 🟠 High | Invalid Data From Multi-axis Acceleration Sensor | Faulty sensor, calibration needed |
| U0433 | 🟠 High | Invalid Data From Cruise Control Front Distance Sensor (Center) | Radar misalignment, dirty sensor |
| U0434 | 🟠 High | Invalid Data From Active Roll Control Module | Suspension module failure, hydraulic issue |
| U0435 | 🟠 High | Invalid Data From Rear Power Steering Control Module | Rear steering actuator fault |
| U0436 | 🟠 High | Invalid Data From Front Differential Control Module | Differential lock malfunction |
| U0437 | 🟠 High | Invalid Data From Rear Differential Control Module | Differential sensor/wiring issue |
| U0438 | 🟡 Medium | Invalid Data From Trailer Brake Control Module | Trailer module fault, connector issue |
| U0439 | 🟡 Medium | Invalid Data From All-Terrain Control Module | Drive mode selector fault |
| U043A | 🟠 High | Invalid Data From Suspension Control Module “B” | Secondary suspension module failure |
| U043B | 🟠 High | Invalid Data From Cruise Control Left Front Distance Sensor | Sensor misalignment, obstruction |
| U043C | 🟠 High | Invalid Data From Cruise Control Right Front Distance Sensor | Damaged sensor, wiring fault |
| U043D | 🔵 Low | ISO/SAE Reserved | Reserved for future use |
| U043E | 🔵 Low | ISO/SAE Reserved | Reserved for future use |
| U043F | 🔵 Low | ISO/SAE Reserved | Reserved for future use |
| U0440 | 🔵 Low | ISO/SAE Reserved | Reserved for future use |
| U0441 | 🔴 Critical | Invalid Data Received From Emissions Control Module | Faulty emissions sensor, CAN bus wiring issue, module failure |
| U0442 | 🔴 Critical | Invalid Data Received From ECM/PCM “B” | PCM/ECM communication error, wiring short, software glitch |
| U0443 | 🟠 High | Invalid Data Received From Body Control Module “B” | BCM fault, corroded connector, CAN bus disruption |
| U0444 | 🟠 High | Invalid Data Received From Body Control Module “C” | Wiring damage, BCM configuration error |
| U0445 | 🟠 High | Invalid Data Received From Body Control Module “D” | Loose ground, faulty BCM, CAN signal interference |
| U0446 | 🟠 High | Invalid Data Received From Body Control Module “E” | BCM software update needed, power supply issue |
| U0447 | 🟠 High | Invalid Data Received From Gateway “A” | Gateway module failure, CAN bus wiring fault |
| U0448 | 🟠 High | Invalid Data Received From Gateway “B” | Faulty gateway, CAN network disruption |
| U0449 | 🟠 High | Invalid Data Received From Gateway “C” | Loose connector, gateway module error |
| U044A | 🟠 High | Invalid Data Received From Gateway “D” | CAN bus termination issue, gateway power loss |
| U0451 | 🟠 High | Invalid Data Received From Gateway “E” | Gateway module failure, CAN bus short circuit |
| U0452 | 🔴 Critical | Invalid Data Received From Restraints Control Module | Airbag/SRS module fault, crash sensor issue |
| U0453 | 🔴 Critical | Invalid Data From Side Restraints Control Module (Left) | Damaged wiring, faulty side-impact sensor |
| U0454 | 🔴 Critical | Invalid Data From Side Restraints Control Module (Right) | Sensor misalignment, connector corrosion |
| U0455 | 🔴 Critical | Invalid Data From Occupant Classification System | Faulty seat weight sensor, wiring damage |
| U0456 | 🟠 High | Invalid Data From Coolant Temperature Control Module | Failed temp sensor, wiring short, ECU issue |
| U0457 | 🟡 Medium | Invalid Data From Information Center “A” | Infotainment system error, CAN communication fault |
| U0458 | 🟡 Medium | Invalid Data From Information Center “B” | Display module failure, software bug |
| U0459 | 🟡 Medium | Invalid Data From Head-Up Display | HUD module power issue, CAN signal loss |
| U045A | 🟡 Medium | Invalid Data From Parking Assist Module “A” | Parking sensor fault, wiring damage |
| U0461 | 🟡 Medium | Invalid Data From Audible Alert Control Module | Chime/buzzer circuit fault, module failure |
| U0462 | 🔵 Low | Invalid Data From Compass Module | Compass sensor calibration needed, loose wiring |
| U0463 | 🟡 Medium | Invalid Data From Navigation Display Module | GPS antenna issue, infotainment software error |
| U0464 | 🟡 Medium | Invalid Data From Navigation Control Module | Map data corruption, module reset required |
| U0465 | 🟠 High | Invalid Data From PTO (Power Take-Off) Control Module | PTO sensor failure, hydraulic system issue |
| U0466 | 🟠 High | Invalid Data From Rear HVAC Control Module | Blower motor fault, climate control module error |
| U0467 | 🟠 High | Invalid Data From Fuel Additive Control Module | DEF system fault, SCR dosing pump issue |
| U0468 | 🔴 Critical | Invalid Data From Fuel Cell Control Module | Hydrogen fuel cell system failure, sensor fault |
| U0469 | 🔴 Critical | Invalid Data From Starter/Generator Control Module | Hybrid system fault, 12V/48V power issue |
| U046A | 🟡 Medium | Invalid Data From Sunroof Control Module | Sunroof motor/sensor fault, wiring short |
| U046B | 🟡 Medium | Invalid Data From GPS Module | Antenna disconnection, software update needed |
| U046C-U0470 | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0471 | 🟠 High | Invalid Data From Restraints System Sensor A | Faulty sensor, wiring issue, communication error |
| U0472 | 🟠 High | Invalid Data From Restraints System Sensor B | Sensor malfunction, CAN bus fault |
| U0473 | 🟠 High | Invalid Data From Restraints System Sensor C | Loose connector, sensor failure |
| U0474 | 🟠 High | Invalid Data From Restraints System Sensor D | Damaged wiring, module conflict |
| U0475 | 🟠 High | Invalid Data From Restraints System Sensor E | Signal interference, sensor fault |
| U0476 | 🟠 High | Invalid Data From Restraints System Sensor F | Corroded terminals, poor ground |
| U0477 | 🟠 High | Invalid Data From Restraints System Sensor G | Short circuit, sensor misalignment |
| U0478 | 🟠 High | Invalid Data From Restraints System Sensor H | Module software bug, power issue |
| U0479 | 🟠 High | Invalid Data From Restraints System Sensor I | Faulty sensor, CAN bus dropout |
| U047A | 🟠 High | Invalid Data From Restraints System Sensor J | Wiring damage, sensor calibration error |
| U047B | 🟠 High | Invalid Data From Restraints System Sensor K | Internal sensor failure |
| U047C | 🟠 High | Invalid Data From Restraints System Sensor L | Communication timeout, signal loss |
| U047D | 🟠 High | Invalid Data From Restraints System Sensor M | Sensor misconfiguration |
| U047E | 🟠 High | Invalid Data From Restraints System Sensor N | Power supply issue to sensor |
| U047F | 🔴 Critical | Invalid Data From Seatbelt Pretensioner Module A | Pretensioner fault, crash data corruption |
| U0480 | 🔴 Critical | Invalid Data From Seatbelt Pretensioner Module B | Wiring short, module failure |
| U0481 | 🟡 Medium | Invalid Data From Automatic Lighting Control Module | Lighting module software bug |
| U0482 | 🟡 Medium | Invalid Data From Headlamp Leveling Control Module | Leveling motor fault, wiring issue |
| U0483 | 🟡 Medium | Invalid Data From Front Lighting Control Module | Loose connector, module reset needed |
| U0484 | 🟡 Medium | Invalid Data From Rear Lighting Control Module A | Bulb failure, ground issue |
| U0485 | 🔵 Low | Invalid Data From Radio | Infotainment system glitch |
| U0486 | 🔵 Low | Invalid Data From Antenna Control Module | Antenna signal loss, wiring fault |
| U0487 | 🔵 Low | Invalid Data From Audio Amplifier A | Amplifier power issue, blown fuse |
| U0488 | 🔵 Low | Invalid Data From Digital Disc Player/Changer A | Disc player communication error |
| U0489 | 🔵 Low | Invalid Data From Digital Disc Player/Changer B | Disc changer mechanical fault |
| U048A | 🔵 Low | Invalid Data From Digital Disc Player/Changer C | Optical lens dirty, disc error |
| U048B-U0490 | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0491 | 🔵 Low | Invalid Data From Digital Disc Player/Changer D | Firmware corruption |
| U0492 | 🔵 Low | Invalid Data From Television | TV tuner signal loss |
| U0493 | 🔵 Low | Invalid Data From Personal Computer | PC interface module fault |
| U0494 | 🔵 Low | Invalid Data From Digital Audio Control Module A | Audio module software bug |
| U0495 | 🔵 Low | Invalid Data From Digital Audio Control Module B | Wiring short in audio system |
| U0496 | 🔵 Low | Invalid Data From Subscription Entertainment Receiver | Subscription module activation issue |
| U0497 | 🔵 Low | Invalid Data From Rear Entertainment Control Module A | Rear screen communication fault |
| U0498 | 🔵 Low | Invalid Data From Telephone Control Module | Bluetooth module failure |
| U0499 | 🟡 Medium | Invalid Data From Telematic Control Module | GPS/telematics unit malfunction |
| U049A | 🟡 Medium | Invalid Data From Door Control Module A | Door lock actuator/wiring issue |
| U049B-U04FF | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0500 | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0501 | 🟡 Medium | Invalid Data From Door Control Module B | Loose connector, CAN bus fault, module failure |
| U0502 | 🟡 Medium | Invalid Data From Door Control Module C | Wiring short, poor ground, software glitch |
| U0503 | 🟡 Medium | Invalid Data From Door Control Module D | Damaged harness, module power issue |
| U0504 | 🟡 Medium | Invalid Data From Door Control Module E | Faulty module, communication protocol mismatch |
| U0505 | 🟡 Medium | Invalid Data From Door Control Module F | Intermittent CAN signal, corroded pins |
| U0506 | 🟡 Medium | Invalid Data From Door Control Module G | Software update needed, module defect |
| U0507 | 🟠 High | Invalid Data From Folding Top Control Module | Roof motor/sensor fault, LIN bus failure |
| U0508 | 🟠 High | Invalid Data From Movable Roof Control Module | Wiring damage, hydraulic system issue |
| U0509 | 🟡 Medium | Invalid Data From Seat Control Module A | Seat motor/wiring fault, connector issue |
| U050A | 🟡 Medium | Invalid Data From Seat Control Module B | Power seat switch failure, CAN disruption |
| U0511 | 🟡 Medium | Invalid Data From Seat Control Module C | Memory seat calibration error, module reset needed |
| U0512 | 🟡 Medium | Invalid Data From Seat Control Module D | Short in seat heater circuit, faulty module |
| U0513 | 🔴 Critical | Invalid Data From Yaw Rate Sensor Module | Stability control disabled, sensor/wiring fault |
| U0514 | 🟡 Medium | Invalid Data From Mirror Control Module | Mirror motor/wiring issue, switch failure |
| U0515 | 🟠 High | Invalid Data From Remote Function Actuation | Key fob signal interference, receiver fault |
| U0516 | 🟡 Medium | Invalid Data From Door Switch A | Faulty switch, wiring short, door latch issue |
| U0517 | 🟡 Medium | Invalid Data From Door Switch B | Corroded contacts, switch misalignment |
| U0518 | 🟡 Medium | Invalid Data From Door Switch C | Broken wire, moisture damage |
| U0519 | 🟡 Medium | Invalid Data From Door Switch D | Grounding issue, switch failure |
| U0521 | 🟡 Medium | Invalid Data From Door Switch F | Wiring harness damage, connector fault |
| U0522 | 🟡 Medium | Invalid Data From Door Switch G | Switch mechanical failure, CAN signal loss |
| U0523 | 🟠 High | Invalid Data From Door Window Motor A | Window motor/wiring fault, regulator issue |
| U0524 | 🟠 High | Invalid Data From Door Window Motor B | Blown fuse, motor overload |
| U0525 | 🟠 High | Invalid Data From Door Window Motor C | Switch failure, module communication error |
| U0526 | 🟠 High | Invalid Data From Door Window Motor D | Wiring short, motor resistance mismatch |
| U0527 | 🟠 High | Invalid Data From Door Window Motor E | Poor battery voltage, motor brush wear |
| U0528 | 🟠 High | Invalid Data From Door Window Motor F | LIN bus fault, motor controller issue |
| U0529 | 🟠 High | Invalid Data From Door Window Motor G | Mechanical binding, module programming error |
| U052A | 🟡 Medium | Invalid Data From Heated Steering Wheel Module | Clock spring fault, heating element failure |
| U050B-U0510 | ⚪ Reserved | ISO/SAE Reserved Codes | N/A |
| U051B-U0520 | ⚪ Reserved | ISO/SAE Reserved Codes | N/A |
| U052B-U0530 | ⚪ Reserved | ISO/SAE Reserved Codes | N/A |
| U0531 | 🟡 Medium | Invalid Data Received From Rear Gate Module | Faulty rear gate module, CAN bus wiring issue, poor connection |
| U0532 | 🟡 Medium | Invalid Data Received From Rain Sensing Module | Rain sensor failure, wiring short, module configuration error |
| U0533 | 🟠 High | Invalid Data From Side Obstacle Detection Module (Left) | Blind-spot sensor fault, damaged wiring, calibration needed |
| U0534 | 🟠 High | Invalid Data From Side Obstacle Detection Module (Right) | Sensor misalignment, CAN communication error |
| U0535 | 🟡 Medium | Invalid Data From Convenience Recall Module | Memory seat/mirror module fault, power supply issue |
| U0536 | 🟠 High | Invalid Data From Lateral Acceleration Sensor Module | Faulty sensor, ESP/ABS system communication error |
| U0537 | 🟠 High | Invalid Data From Column Lock Module | Steering column lock failure, ignition switch issue |
| U0538 | 🟡 Medium | Invalid Data From Digital Audio Control Module “C” | Infotainment system software bug, wiring fault |
| U0539 | 🟡 Medium | Invalid Data From Digital Audio Control Module “D” | Amplifier/module communication error |
| U053A | 🟠 High | Invalid Data From Entrapment Control Module “A” | Power window/lift module failure, safety system error |
| U053B | 🟠 High | Invalid Data From Image Processing Module “A” | Camera/ADAS system fault, corrupted data |
| U053C | 🟠 High | Invalid Data From Image Processing Module “B” | Lane-keep assist/camera module issue |
| U053D | 🟠 High | Invalid Data From Image Processing Module “C” | Night vision/thermal camera fault |
| U053E-F | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0541 | 🟠 High | Invalid Data From Entrapment Control Module “B” | Sunroof/power window safety circuit fault |
| U0542 | 🟡 Medium | Invalid Data From Headlamp Control Module “A” | Adaptive headlight failure, wiring issue |
| U0543 | 🟡 Medium | Invalid Data From Headlamp Control Module “B” | LED/Matrix headlight communication error |
| U0544 | 🟠 High | Invalid Data From Parking Assist Module “B” | 360° camera/sensor fault, calibration needed |
| U0545 | 🟡 Medium | Invalid Data From Running Board Control Module | Power running board motor/switch failure |
| U0546 | 🔵 Low | Invalid Data From Front Entertainment Control Module | Rear-seat infotainment system glitch |
| U0547 | 🟡 Medium | Invalid Data From Seat Control Module “E” | Massage seat/memory module communication error |
| U0548 | 🟡 Medium | Invalid Data From Seat Control Module “F” | Passenger seat sensor/control issue |
| U0549 | 🟡 Medium | Invalid Data From Remote Accessory Module | Keyless entry/remote start system fault |
| U054A | 🔵 Low | Invalid Data From Rear Entertainment Module “B” | HDMI/USB port communication error |
| U054B | 🔵 Low | Invalid Data From Interior Lighting Control Module | Ambient lighting module/wiring issue |
| U054C-F | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0551 | 🔴 Critical | Invalid Data From Impact Classification System | Crash sensor/airbag module failure (safety risk!) |
| U0552 | 🟡 Medium | Invalid Data From Running Board Control Module “B” | Secondary running board actuator fault |
| U0553 | 🟡 Medium | Invalid Data From Rear Lighting Control Module “B” | Taillight/DRL module communication error |
| U0554 | 🟡 Medium | Invalid Data From Accessory Protocol Interface | Aftermarket accessory interference |
| U0555 | 🟠 High | Invalid Data From Remote Start Module | Remote start system failure, antenna issue |
| U0556 | 🟡 Medium | Invalid Data From Front Display Interface Module | Instrument cluster/dash display glitch |
| U0557 | 🟡 Medium | Invalid Data From Front Controls Interface “A” | Touchscreen/HVAC control module error |
| U0558 | 🟡 Medium | Invalid Data From Front Controls/Display Module | Infotainment head unit software crash |
| U0559 | 🟡 Medium | Invalid Data From Radio Transceiver | Satellite radio/GPS antenna fault |
| U055A-D | 🟡 Medium | Invalid Data From Special Purpose Vehicle Modules | Commercial/emergency vehicle equipment fault |
| U055E | 🟡 Medium | Invalid Data From Front Controls Interface “B” | Secondary control panel (e.g., rear-seat) issue |
| U055F-60 | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0561 | 🟡 Medium | Invalid Data From Seat Control Switch Module “A” | Faulty seat switch, wiring issue, CAN bus communication error |
| U0562 | 🟡 Medium | Invalid Data From Seat Control Switch Module “B” | Loose connector, module failure, data corruption |
| U0563 | 🟡 Medium | Invalid Data From Audio Amplifier “B” | Amplifier fault, wiring short, infotainment system error |
| U0564 | 🟡 Medium | Invalid Data From Speech Recognition Module | Microphone failure, software glitch, wiring issue |
| U0565 | 🟠 High | Invalid Data From Rear Camera Module | Camera malfunction, corroded connector, video signal loss |
| U0566 | ⚪ Reserved | ISO/SAE Reserved | N/A |
| … | ⚪ Reserved | (Codes U0567-U0586 reserved by ISO/SAE) | N/A |
| U0587 | 🟠 High | Invalid Data From Radiator Anti-Tamper Device | Tampering detected, module failure, CAN bus issue |
| U0588 | 🔴 Critical | Invalid Data From Transmission Fluid Pump Module | Pump control failure, low fluid, wiring short |
| U0589 | 🟠 High | Invalid Data From DC/AC Converter Module “A” | Converter fault, voltage irregularity, communication error |
| U058A | 🟠 High | Invalid Data From DC/AC Converter Module “B” | Wiring damage, module malfunction |
| U058B | ⚪ Reserved | ISO/SAE Reserved | N/A |
| U0592 | 🟠 High | Invalid Data From Gear Shift Control Module “B” | Shifter sensor failure, CAN bus disruption |
| U0593 | 🔴 Critical | Invalid Data From Drive Motor Control Module “B” | Motor controller fault, HV system error |
| U0594 | 🔴 Critical | Invalid Data From Hybrid Powertrain Control Module | Hybrid system failure, software corruption |
| U0595 | 🟠 High | Invalid Data From Powertrain Control Monitor Module | PCM communication error, wiring issue |
| U0596 | 🟠 High | Invalid Data From AC/AC Converter Control Module | Converter overheating, signal interference |
| U0597 | 🟠 High | Invalid Data From AC/DC Converter Module “A” | Voltage fluctuation, module failure |
| U0598 | 🟠 High | Invalid Data From AC/DC Converter Module “B” | Short circuit, firmware bug |
| U0599 | 🟠 High | Invalid Data From DC/DC Converter Module “A” | 12V battery issue, converter fault |
| U059A | 🟠 High | Invalid Data From DC/DC Converter Module “B” | Wiring damage, communication loss |
| U059B | 🔴 Critical | Invalid Data From Hybrid Battery Pack Sensor Module | Battery sensor failure, HV safety risk |
| U059C | 🔴 Critical | Invalid Data From Drive Motor Control Module “C” | Motor encoder fault, CAN timeout |
| U059D | 🔴 Critical | Invalid Data From Drive Motor Control Module “D” | Phase current mismatch, resolver error |
| U059E | 🟠 High | Invalid Data From NOx Sensor “A” | Sensor contamination, DEF system fault |
| U059F | 🟠 High | Invalid Data From NOx Sensor “B” | Exhaust leak, sensor wiring damage |
| U05A0 | ⚪ Reserved | ISO/SAE Reserved (through U05FF & U0600) | N/A |
| U1000 | 🟠 High | Class 2 Communication Malfunction | CAN bus wiring fault, loose connectors, low system voltage |
| U0100 | 🟠 High | Lost Communication with ECM/PCM | Faulty PCM, CAN bus disruption, wiring short/open |
| U0101 | 🟠 High | Lost Communication with TCM | TCM failure, network wiring issue, poor power/ground |
| U0121 | 🟠 High | Lost Communication with ABS Control Module | ABS module unresponsive, CAN bus fault, blown fuse |
| U0140 | 🟠 High | Lost Communication with BCM | Body Control Module failure, wiring issue, network error |
| U0155 | 🟠 High | Lost Communication with Instrument Cluster | Cluster power issue, CAN bus fault, faulty instrument panel |
| U0167 | 🟡 Medium | Lost Communication with A/C Control Module | HVAC module fault, wiring issue, low refrigerant pressure |
| U0184 | 🟡 Medium | Lost Communication with Audio System | Radio/Nav unit failure, MOST bus fault, wiring issue |
| U0300 | 🟠 High | Internal Control Module Software Incompatibility | Software mismatch, incorrect programming, module replacement needed |
| U0401 | 🟡 Medium | Invalid Data Received from ECM | ECM communication error, corrupted data, CAN bus glitch |
| U0415 | 🟡 Medium | Invalid Data Received from ABS Control Module | ABS module data corruption, signal interference |
| U0422 | 🟡 Medium | Invalid Data Received from BCM | BCM configuration error, faulty sensor input |
| U1001 | 🟡 Medium | SCP (J1850) Invalid or Missing Data | J1850 bus fault, module communication error |
| U2100 | 🟠 High | CAN Bus Off | CAN bus short to ground/power, termination resistor failure |
| U3000 | 🔴 Critical | Control Module Power Malfunction | No power to module, blown fuse, ignition circuit failure |
| U3003 | 🔴 Critical | Battery Voltage Out of Range | Alternator failure, battery drain, wiring issue |
📚 U1xxx Manufacturer Specific Network Codes
(Color Key: 🔴 Critical | 🟠 High | 🟡 Medium | 🔵 Low)
| DTC Code | Severity | Description | Possible Causes |
|---|---|---|---|
| U1000 | 🟠 High | Class 2 Communication Malfunction | CAN bus wiring fault, loose connectors, low system voltage |
| U0100 | 🟠 High | Lost Communication with ECM/PCM | Faulty PCM, CAN bus disruption, wiring short/open |
| U0101 | 🟠 High | Lost Communication with TCM | TCM failure, network wiring issue, poor power/ground |
| U0121 | 🟠 High | Lost Communication with ABS Control Module | ABS module unresponsive, CAN bus fault, blown fuse |
| U0140 | 🟠 High | Lost Communication with BCM | Body Control Module failure, wiring issue, network error |
| U0155 | 🟠 High | Lost Communication with Instrument Cluster | Cluster power issue, CAN bus fault, faulty instrument panel |
| U0167 | 🟡 Medium | Lost Communication with A/C Control Module | HVAC module fault, wiring issue, low refrigerant pressure |
| U0184 | 🟡 Medium | Lost Communication with Audio System | Radio/Nav unit failure, MOST bus fault, wiring issue |
| U0300 | 🟠 High | Internal Control Module Software Incompatibility | Software mismatch, incorrect programming, module replacement needed |
| U0401 | 🟡 Medium | Invalid Data Received from ECM | ECM communication error, corrupted data, CAN bus glitch |
| U0415 | 🟡 Medium | Invalid Data Received from ABS Control Module | ABS module data corruption, signal interference |
| U0422 | 🟡 Medium | Invalid Data Received from BCM | BCM configuration error, faulty sensor input |
| U1001 | 🟡 Medium | SCP (J1850) Invalid or Missing Data | J1850 bus fault, module communication error |
| U2100 | 🟠 High | CAN Bus Off | CAN bus short to ground/power, termination resistor failure |
| U3000 | 🔴 Critical | Control Module Power Malfunction | No power to module, blown fuse, ignition circuit failure |
| U3003 | 🔴 Critical | Battery Voltage Out of Range | Alternator failure, battery drain, wiring issue |
📚 U2XXX & U3XXX Network Codes
(Color Key: 🔴 Critical | 🟠 High | 🟡 Medium | 🔵 Low | ⚪ Info/Reserved)
| DTC Code | Severity | Description | Possible Causes |
|---|---|---|---|
| U2000 | ⚪ Info | Manufacturer-Specific DTC | Varies by OEM (check service manual) |
| U3000 | 🟠 High | Control Module General Malfunction | Module internal failure, software corruption |
| U3001 | 🟡 Medium | Control Module Improper Shutdown | Interrupted power, faulty ignition switch, wiring issue |
| U3002 | 🟠 High | Vehicle Identification Number (VIN) Mismatch | Incorrect VIN programming, module replacement without reprogramming |
| U3003 | 🟠 High | Battery Voltage Out of Range | Weak/dead battery, charging system fault, poor connections |
| U3004 | 🟡 Medium | Accessory Power Relay Circuit Malfunction | Relay failure, blown fuse, wiring short/open |
| U3005 | 🟡 Medium | Retained Accessory Power Circuit Issue | Faulty RAP relay, wiring problem, module fault |
| U3006 | 🔴 Critical | Control Module Input Power “A” Circuit Fault | Open fuse, broken wire, poor ground connection |
| U3007 | 🔴 Critical | Control Module Input Power “B” Circuit Fault | Short circuit, corroded connector, module failure |
| U3008 | 🔴 Critical | Control Module Ground “A” Circuit Fault | Loose/corroded ground, damaged wiring |
| U3009 | 🔴 Critical | Control Module Ground “B” Circuit Fault | Poor chassis ground, wiring damage |
| U300A | 🟠 High | Ignition Switch Circuit Malfunction | Faulty ignition switch, wiring issue |
| U300B | 🟠 High | Ignition Input (Accessory/On/Start) Signal Issue | Wiring short/open, faulty switch, module problem |
| U300C | 🟠 High | Ignition Input (Off/On/Start) Signal Issue | Ignition switch failure, wiring fault |
| U300D | 🟠 High | Ignition Input (On/Start) Signal Issue | Broken wire, poor connection, module error |
| U300E | 🟠 High | Ignition Input (On) Signal Issue | Faulty ignition switch, wiring short |
| U300F | 🟠 High | Ignition Input (Accessory) Signal Issue | Wiring problem, switch failure |
| U3010 | 🟠 High | Ignition Input (Start) Signal Issue | Starter relay fault, ignition switch problem |
| U3011 | 🟠 High | Ignition Input (Off) Signal Issue | Stuck ignition switch, wiring short |
| U3012-U30FF | ⚪ Info | ISO/SAE Reserved Codes | Reserved for future standardization |
| U3100 | ⚪ Info | ISO/SAE Reserved Code | Reserved for future use |
Severity Guide
-
- 🔴 Critical: Module power/ground failure (vehicle may not start or operate).
- 🟠 High: Ignition/voltage issues (affects drivability or safety systems).
- 🟡 Medium: Accessory/retained power faults (may disable non-essential features).
- 🔵 Low: Minor electrical glitches (often intermittent).
- ⚪ Info: Reserved codes or manufacturer-specific (no immediate action).
Common Root Causes
-
- Wiring faults: Shorts, opens, corrosion.
- Ignition switch issues: Wear, electrical failure.
- Module failures: Software corruption, hardware damage.
- Battery/charging problems: Low voltage, poor connections.
Check Also:
- 🔗Understanding Body Control Module & Occupant Safety System DTCs B-Code
- 🔗Understanding Chassis C-Code
