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OBD-II Chassis C – Codes
This reference table provides a comprehensive list of Diagnostic Trouble Codes (DTCs), OBD-II Chassis C – Codes related to vehicle ABS, traction control, wheel speed sensors, suspension systems, and other electronic control modules. These codes help technicians identify malfunctions in various circuits, sensors, and control systems, ensuring accurate diagnostics and efficient repairs.
The table includes:
-
- DTC Codes (e.g., C0035, C0221)
- Descriptions of each fault (e.g., “Left Front Wheel Speed Circuit Malfunction”)
ABS, Traction Control & Suspension DTCs with Severity & Causes
Severity Guide
- 🔴 Critical – Immediate safety risk (e.g., brake failure, loss of stability control).
- 🟠 High – System malfunction (e.g., ABS disabled, wheel speed errors).
- 🟡 Moderate – Performance issue (e.g., sensor faults, minor electrical problems).
- 🔵 Low – Non-critical (e.g., warning lamp circuit, minor communication errors).
📚 C – Generic OBD-II Chassis Codes
Diagnostic Trouble Code (DTC) Reference Table
(Color Key: 🔴 Critical | 🟠 High | 🟡 Medium | 🔵 Low)
| DTC Code | Severity | Description | Possible Causes |
|---|---|---|---|
| C0000 | 🔴 Critical | Vehicle Speed Information Circuit Malfunction | Faulty speed sensor, wiring issue, PCM communication error |
| C0035 | 🟠 High | Left Front Wheel Speed Circuit Malfunction | Damaged sensor, broken wiring, poor connection |
| C0040 | 🟠 High | Right Front Wheel Speed Circuit Malfunction | Sensor failure, corroded connector, ABS module fault |
| C0041 | 🟡 Medium | Right Front Wheel Speed Sensor Range/Performance | Misaligned sensor, damaged tone ring, erratic signal |
| C0045 | 🟠 High | Left Rear Wheel Speed Circuit Malfunction | Sensor/wiring fault, ABS module issue |
| C0050 | 🟠 High | Right Rear Wheel Speed Circuit Malfunction | Short/open circuit, faulty sensor |
| C0110 | 🔴 Critical | Pump Motor Circuit Malfunction | Pump motor failure, relay/wiring issue |
| C0121 | 🟠 High | Valve Relay Circuit Malfunction | Stuck relay, wiring short, ABS module fault |
| C0128 | 🔴 Critical | Low Brake Fluid Circuit | Low brake fluid, faulty level sensor |
| C0221 | 🟠 High | Right Front Wheel Speed Sensor Circuit Open | Broken wire, disconnected sensor |
| C0223 | 🟡 Medium | Right Front Wheel Speed Signal Erratic | Dirty sensor, damaged tone ring |
| C0238 | 🟠 High | Wheel Speed Mismatch | Uneven tire sizes, ABS module fault |
| C0267 | 🔴 Critical | Pump Motor Circuit Open/Shorted | Burnt motor, wiring damage |
| C0271 | 🔴 Critical | EBCM Malfunction | Internal ABS module failure |
| C0290 | 🔴 Critical | Lost Communications With PCM | CAN bus fault, wiring issue, PCM failure |
| C0298 | 🟠 High | Powertrain Indicated Traction Control Malfunction | PCM/ABS conflict, sensor issue |
| C0550 | 🟠 High | ECU Internal Write/Checksum Malfunction | Software corruption, ECU failure |
| C0750 | 🟡 Medium | Tire Pressure Monitor (TPM) Sensor Not Transmitting | Dead sensor battery, signal interference |
| C0800 | 🟠 High | Device Power #1 Circuit Malfunction | Blown fuse, wiring short, module failure |
| C0896 | 🟠 High | ESC Voltage Out of Range (9-15.5V) | Alternator fault, voltage regulator issue |
Severity Color Guide
-
- 🔴 Critical: Immediate safety risk (e.g., ABS/pump failure, no speed data).
- 🟠 High: Major system dysfunction (e.g., wheel speed loss, TCS disabled).
- 🟡 Medium: Reduced performance (e.g., erratic signals, minor electrical faults).
- 🔵 Low: Non-safety related (e.g., warning light circuit issues).
Notes
-
- Critical/High codes should be addressed immediately.
- Medium codes may trigger limp mode or warnings.
- Low codes often relate to secondary systems (e.g., dashboard lights).
📚 GM – Chevrolet – GMC Chassis Codes
| DTC | Severity | Description | Possible Causes |
|---|---|---|---|
| C1211 | 🟠 High | ABS Indicator Lamp Circuit Malfunction | Blown fuse, wiring short/open, faulty ABS module |
| C1214 | 🔴 Critical | System Relay Contact/Coil Circuit Open | Failed relay, wiring break, poor connection |
| C1217 | 🔴 Critical | Pump Motor Shorted to Ground | Damaged pump motor, wiring short, faulty EBCM |
| C1218 | 🔴 Critical | Pump Motor Shorted to Voltage/Ground Open | Wiring short to power, open ground, faulty pump |
| C1221 | 🟠 High | LF Wheel Speed Sensor = 0 | Failed sensor, wiring break, poor connection, tone ring damage |
| C1222 | 🟠 High | RF Wheel Speed Sensor = 0 | Failed sensor, wiring break, poor connection, tone ring damage |
| C1225 | 🟠 High | LF Excessive Wheel Speed Variation | Damaged tone ring, bad wheel bearing, sensor alignment |
| C1232 | 🟠 High | LF Wheel Speed Circuit Open/Shorted | Wiring damage, corroded connector, faulty sensor |
| C1236 | 🟠 High | Low System Voltage | Weak battery, charging system fault, poor grounds |
| C1237 | 🟠 High | High System Voltage | Faulty alternator, voltage regulator issue |
| C1242 | 🔴 Critical | Pump Motor Circuit Open | Blown fuse, wiring break, failed pump motor |
| C1243 | 🔴 Critical | BPMV Pump Motor Stalled | Mechanical seizure, electrical fault, low voltage |
| C1255 | 🔴 Critical | EBCM Internal Malfunction | Module failure, water damage, internal short |
| C1261 | 🟠 High | LF Inlet Valve Solenoid Fault | Stuck valve, wiring issue, solenoid failure |
| C1276 | 🟠 High | Delivered Torque Signal Fault | CAN bus issue, PCM communication error |
| C1281 | 🟠 High | VSES Sensors Uncorrelated | Yaw rate sensor fault, steering angle sensor issue |
| C1282 | 🟠 High | Yaw Rate Sensor Bias Fault | Sensor calibration needed, internal failure |
| C1291 | 🟠 High | Brake Lamp Switch Open During Decel | Faulty switch, wiring issue, adjustment needed |
| C1296 | 🟠 High | Brake Pressure Sensor Fault | Failed sensor, wiring issue, hydraulic problem |
| C1710 | 🟠 High | LF Damper Short to Battery | Wiring short, actuator failure, control module issue |
| C1760 | 🟡 Moderate | LF Position Sensor Fault | Sensor failure, wiring issue, calibration needed |
| C1780 | 🟠 High | Loss of Steering Position Signal | Sensor failure, wiring break, clock spring issue |
Key Columns Explained
-
- DTC Code – The diagnostic trouble code number
- Severity – Color-coded priority level
- Description – What the code indicates
- Possible Causes – Most common root causes
How to Use This Table
-
- 🔴 Critical Codes – Address immediately (e.g., pump motor failure, EBCM faults).
- 🟠 High Priority – Diagnose ASAP (e.g., wheel speed sensor loss, valve solenoid issues).
- 🟡 Moderate – Schedule repair (e.g., sensor calibration, minor electrical faults).
- 🔵 Low – Monitor (e.g., warning lamp circuits, non-critical comm errors).
Typical Repair Approach
-
- Check wiring/connectors (50% of issues are connection-related)
- Verify sensor operation (Test resistance/signal output)
- Inspect mechanical components (Tone rings, wheel bearings)
- Module diagnostics (Scan tool live data, module programming)
(Note: Causes may vary by vehicle make/model – always consult service manual for specific applications)
