Get the complete OEM workshop document for the 2013-2014 Infiniti Hybrid repair manual (M35, M37, M45 and M56) Model HY51 Series, with the wiring diagram in PDF.
Overview
The 2013–2014 Infiniti M Hybrid (Y51) pairs a 3.5L V6 with an electric motor integrated into a 7-speed automatic, delivering strong acceleration with better fuel efficiency than the V8 M56. It is rear-wheel drive only and uses a compact lithium-ion battery mounted behind the rear seats. The result is a quick, quiet luxury sedan with unique hybrid complexity that buyers should understand before ownership.
Technical Specs
- Platform: Infiniti M (Y51) midsize luxury sedan
- Powertrain: 3.5L V6 + electric motor (parallel hybrid)
- Combined output: 360 hp (approx.)
- Transmission: 7-speed automatic (hybrid-specific)
- Drivetrain: Rear-wheel drive
- Battery: Lithium-ion hybrid battery (rear-mounted)
- Fuel economy (real-world): mid-20s mpg combined (driving style dependent)
Performance & Driving
The M Hybrid is noticeably quicker than most luxury hybrids of its era, with instant electric torque filling in
low-RPM gaps. Steering and chassis balance lean sporty, but added hybrid weight affects rear cargo space and long-term service complexity. Ride comfort remains firmly luxury-oriented.
Top 10 Common Mechanical Issues (Reported by Owners)
- Hybrid battery degradation
Symptoms: Reduced EV assist, warning messages, lower fuel economy
Root Cause: Normal lithium-ion aging, heat exposure, high mileage
Fix: Battery capacity test; replace hybrid battery if below threshold
Cost to Fix: $3,500–$6,500 - Transmission hesitation or harsh shifts
Symptoms: Jerky takeoff, delayed engagement, rough gear changes
Root Cause: Hybrid-specific transmission control calibration or fluid degradation
Fix: Software update; fluid service; adaptation reset
Cost to Fix: $300–$1,200 - Cooling system leaks
Symptoms: Coolant smell, low coolant warning, overheating risk
Root Cause: Aging hoses or radiator seams
Fix: Pressure test; replace leaking components; bleed system properly
Cost to Fix: $250–$900 - Motor-generator bearing noise
Symptoms: Whining or humming during acceleration
Root Cause: Wear inside hybrid motor assembly
Fix: Confirm with hybrid diagnostics; motor service or replacement
Cost to Fix: $2,000–$4,000 - Engine mount wear
Symptoms: Vibration at idle, clunk on acceleration
Root Cause: Hydraulic mount degradation
Fix: Replace worn mounts; inspect exhaust alignment
Cost to Fix: $600–$1,400 - Brake rotor warping
Symptoms: Steering wheel shake during braking
Root Cause: Heavy vehicle weight and heat buildup
Fix: Replace rotors and pads; torque wheels correctly
Cost to Fix: $400–$900 - Power steering fluid seepage
Symptoms: Whining noise, heavy steering
Root Cause: Hose or seal aging
Fix: Replace leaking hose/seal; flush system
Cost to Fix: $250–$700 - Exhaust flex pipe failure
Symptoms: Rattling noise, exhaust smell
Root Cause: Heat cycling and vibration
Fix: Replace flex section or exhaust component
Cost to Fix: $300–$1,000 - Suspension bushing wear
Symptoms: Clunks over bumps, uneven tire wear
Root Cause: Rubber bushing fatigue
Fix: Replace affected bushings; perform alignment
Cost to Fix: $500–$1,500 - Accessory belt noise
Symptoms: Squealing on startup
Root Cause: Belt glazing or tensioner wear
Fix: Replace belt and tensioner
Cost to Fix: $150–$350
Top 10 Common Electrical Issues (Reported by Owners)
- Hybrid system warning light
Symptoms: Hybrid warning message, reduced power
Root Cause: Battery sensor faults or inverter communication errors
Fix: Scan hybrid control module; repair wiring or replace sensor/module
Cost to Fix: $300–$2,500 - 12-volt battery drain
Symptoms: No-start, repeated dead battery
Root Cause: Parasitic draw or weak auxiliary battery
Fix: Parasitic draw test; replace battery; update software if needed
Cost to Fix: $180–$600 - Infotainment system freezing
Symptoms: Screen lockups, rebooting
Root Cause: Software instability or aging hardware
Fix: Software update or head unit replacement
Cost to Fix: $150–$1,800 - Backup camera failure
Symptoms: Blank or flickering image
Root Cause: Camera module or trunk harness fatigue
Fix: Inspect wiring; replace camera
Cost to Fix: $250–$700 - Smart key detection issues
Symptoms: Intermittent key recognition
Root Cause: Weak fob battery or antenna faults
Fix: Replace battery; test antennas; reprogram key
Cost to Fix: $50–$450 - ABS/VDC warning lights
Symptoms: ABS or traction control light illuminated
Root Cause: Wheel speed sensor failure or low voltage
Fix: Replace sensor; test charging system
Cost to Fix: $200–$900 - Power seat malfunction
Symptoms: Seat stuck or slow movement
Root Cause: Motor or switch failure
Fix: Replace motor or switch assembly
Cost to Fix: $300–$1,200 - HVAC control module errors
Symptoms: Incorrect vent operation or temperature
Root Cause: Actuator or control module fault
Fix: Replace actuator; recalibrate HVAC system
Cost to Fix: $250–$900 - TPMS warning light
Symptoms: Constant tire pressure warning
Root Cause: Sensor battery depletion
Fix: Replace TPMS sensors; reprogram
Cost to Fix: $200–$600 - Instrument cluster glitches
Symptoms: Flickering gauges or warning lights
Root Cause: Internal circuit wear or voltage issues
Fix: Repair or replace cluster; verify grounds
Cost to Fix: $400–$1,500
Pros & Cons
| Pros | Cons |
|---|---|
| Strong acceleration for a hybrid | Complex hybrid repairs |
| Luxury interior and ride quality | Limited trunk space |
| Better fuel economy than V8 M56 | Battery replacement cost |
| Quiet operation in city driving | RWD only |
| Unique market position | Technology feels dated |
Maintenance Schedule
| Interval | Service | Notes |
|---|---|---|
| Every 5,000 mi | Oil & filter, inspect brakes | Short trips require strict intervals |
| Every 15,000 mi | Tire rotation, cabin filter | Watch rear tire wear |
| Every 30,000 mi | Engine air filter, brake fluid check | Hybrid regen reduces pad wear |
| Every 60,000 mi | Transmission service (severity-based) | Hybrid-specific procedure |
| Every 100,000 mi | Coolant, spark plugs | Inspect hybrid cooling components |
Top 5 Competitors
1. Lexus GS 450h (2013-2014) ↗
- Similar hybrid luxury sedan concept with stronger reliability reputation
- More powerful V6 hybrid system (338 hp)
- Better resale value and lower maintenance costs
2. BMW ActiveHybrid 5 (2013-2014) ↗
- German luxury with hybrid efficiency
- More engaging driving dynamics
- Similar power output but sportier handling
3. Mercedes-Benz E400 Hybrid (2014) ↗
- Direct competitor in luxury hybrid segment
- Comparable performance and efficiency
- Stronger brand prestige
4. Acura RLX Sport Hybrid (2014+) ↗
- Honda’s luxury hybrid with all-wheel drive via rear electric motors
- More advanced hybrid system
- Better reliability expected from Honda/Acura
5. Hyundai Genesis/Equus (2013-2014) ↗
- Non-hybrid but worth considering for value
- Similar luxury features at lower price point
- Better warranty coverage
Major Safety Recalls, Advisories & Safety Alerts
1. Driveshaft Failure (Recall R24A5/R24A7 – August 2024)
- Affects 2012-2013 M35 Hybrid vehicles; driveshaft can fatigue and break due to reduced fatigue strength from a supplier specification change Cars.com ↗ – Kelley Blue Book ↗
- Risk: Complete loss of drive power or vehicle rollaway when in park without parking brake applied
- Fix: Free driveshaft replacement at dealers
2. Throttle Position Sensor Software Error (2014)
- Affects 2013-2014 M35 Hybrid (April 2012-September 2013 production); ECM software error can cause unexpected acceleration if throttle position sensor signal is lost then restored Consumer Reports ↗
- Risk: Unintended acceleration increasing crash risk
- Fix: Free ECM reprogramming
3. Fuel Pressure Sensor (2015)
- Affects 2012-2013 M56 and certain 2014-2015 Q70 V8 models; fuel pressure sensors may not have been sufficiently tightened during production Cars.com ↗
- Risk: Fuel leak potentially causing vehicle fire
- Fix: Dealers re-torque fuel pressure sensors free of charge
4. Occupant Classification System (OCS) Malfunction (2016)
- Affects various 2013-2016 Nissan/Infiniti vehicles including 2014 Q50 Hybrid; front passenger OCS may incorrectly classify adult as child or seat as empty Cars.com ↗
- Risk: Passenger airbag may not deploy in crash, increasing injury risk
- Fix: OCS ECU replacement/reprogramming
Hybrid-Specific Issues
5. Electric Motor Failure (2014)
- Affects 2014 Q50/Q70 Hybrid (late 2013-mid 2014 production); software error may cause electric motor to stop while driving in EV mode Cars.com ↗
- Risk: Stall-like condition increasing crash risk
- Fix: Motor inverter software reprogramming
6. Transmission Housing Damage (2014)
- Affects 2014 Q50/Q70 Hybrid (October 2013-January 2014 production); transmission housings may have been damaged during manufacturing Cars.com ↗
- Risk: Housing could crack creating road debris and disabling vehicle
- Fix: Transmission inspection and replacement if cracks found
Technical Service Bulletins
7. Poor Heater Performance – Passenger Side (TSB 12/1/2017)
- Affects 2011-2013 M and M Hybrid, 2014-2015 Q70 and Q70 Hybrid models CarMD ↗
- Issue: Inadequate heating on passenger side of cabin
- Fix: Service procedure available at dealers
8. EVAP Leak Codes (TSB 1/29/2019)
- Affects all 2012 and newer Infiniti vehicles; diagnostic information for EVAP leak codes P0442, P0455, P0456 CarMD ↗
- Issue: Check engine light for evaporative emissions system
- Fix: Diagnostic guidelines provided to technicians
9. Vehicle Pull/Drift Diagnosis (TSB 5/14/2018)
- Affects multiple Infiniti models including M/Q70 series
- Issue: Vehicle pulling to one side or steering wheel off-center
- Fix: Diagnostic procedure for alignment and steering concerns
10. Clicking Noise from Axles (TSB 1/17/2020)
- Affects multiple Infiniti models; clicking noise from front or rear axle during take-off/acceleration CarMD ↗
- Issue: CV joint or axle noise during acceleration
- Fix: Service procedure with Molykote M77 grease application
Important Notes for Buyers
- Check VIN for open recalls at infiniti.com/owners/recalls or NHTSA.gov before purchase
- The 2024 driveshaft recall is relatively recent – ensure it’s been completed
- Hybrid system software updates are critical for safe operation
- Many TSBs are diagnostic aids and may not be covered under warranty
- Pre-purchase inspection by Infiniti specialist highly recommended to check hybrid battery health and verify all recalls completed
Always verify open recalls using your VIN through official Infiniti recall tools.
DTC Trouble Code Tables
Engine Control Module (ECM)
| Code | Description | Cause | Fix |
|---|---|---|---|
| P0300 | Random Misfire | Ignition or fuel issue | Inspect plugs, coils |
| P0171 | System Too Lean | Vacuum leak | Smoke test intake |
| P0420 | Catalyst Efficiency | Aging catalyst | Replace converter |
| P0100 | MAF Circuit | Dirty or failed sensor | Clean or replace |
| P0128 | Coolant Temp Below Regulating | Thermostat stuck | Replace thermostat |
| P0440 | EVAP System | Loose hose | Repair EVAP |
| P0455 | EVAP Large Leak | Cracked line | Smoke test |
| P2195 | O2 Sensor Lean | Sensor fault | Replace sensor |
| P0606 | ECM Failure | Internal fault | Reprogram/replace |
| P1604 | Startability Fault | Low voltage | Test battery |
Transmission Control Module (TCM)
| Code | Description | Cause | Fix |
|---|---|---|---|
| P0700 | TCM Request MIL | Stored fault | Scan TCM |
| P0715 | Input Speed Sensor | Sensor fault | Replace sensor |
| P0720 | Output Speed Sensor | Sensor fault | Replace sensor |
| P0730 | Incorrect Gear Ratio | Low fluid | Service transmission |
| P0744 | TCC Intermittent | Solenoid issue | Replace solenoid |
| P0750 | Shift Solenoid A | Electrical fault | Repair wiring |
| P0776 | Pressure Control Solenoid | Valve body wear | Repair valve body |
| P0796 | Pressure Control Solenoid C | Hydraulic fault | Service valve body |
| P0840 | Fluid Pressure Sensor | Sensor fault | Replace sensor |
| P0894 | Component Slipping | Clutch wear | Overhaul transmission |
ABS / ESC
| Code | Description | Cause | Fix |
|---|---|---|---|
| C1101 | ABS Pump | Voltage issue | Check battery |
| C1110 | Wheel Speed Sensor | Sensor fault | Replace sensor |
| C1143 | Yaw Sensor | Calibration lost | Recalibrate |
| C1155 | Steering Angle Sensor | Misalignment | Relearn angle |
| C1163 | ABS Actuator | Internal fault | Replace actuator |
| C1180 | Brake Switch | Switch fault | Replace switch |
| C1195 | Hydraulic Pressure | Leak | Repair leak |
| C1201 | ECM Signal | Engine fault | Fix engine code |
| C1234 | ABS Relay | Relay fault | Replace relay |
| C1300 | ABS ECU | Module failure | Replace ECU |
SRS Airbag System
| Code | Description | Cause | Fix |
|---|---|---|---|
| B1018 | Airbag Module | Internal fault | Replace module |
| B1049 | Seat Belt Pretensioner | Connector issue | Repair wiring |
| B1054 | Occupant Sensor | Sensor failure | Replace sensor |
| B1065 | Side Airbag | Seat wiring | Repair harness |
| B1070 | Curtain Airbag | Connector fault | Repair connector |
| B1101 | Crash Sensor | Sensor fault | Replace sensor |
| B1129 | Passenger Airbag | OCS error | Recalibrate |
| B1134 | Driver Airbag | Clock spring | Replace clock spring |
| B1145 | Seat Sensor | Wiring issue | Repair wiring |
| B1200 | SRS ECU | Internal fault | Replace ECU |
Body Control / CAN Communication
| Code | Description | Cause | Fix |
|---|---|---|---|
| U0100 | Lost Comm ECM | CAN wiring | Repair CAN |
| U0121 | Lost Comm ABS | Module offline | Check power |
| U0140 | Lost Comm BCM | BCM fault | Repair BCM |
| U0155 | Lost Comm Cluster | Network issue | Repair wiring |
| U0164 | Lost Comm HVAC | HVAC module | Repair module |
| B2109 | Ignition Relay | Relay fault | Replace relay |
| B2190 | Key Antenna | Antenna failure | Replace antenna |
| B2312 | Door Lock Circuit | Actuator fault | Replace actuator |
| B2618 | Lighting Control | BCM issue | Repair BCM |
| U1000 | CAN Comm Line | Network fault | Diagnose CAN |
Frequently Asked Questions For Buyers
1. What hybrid system does the M Hybrid use? The M Hybrid uses a 3.5L V6 engine paired with a 50 kW electric motor for a combined 360 horsepower. It features a lithium-ion battery pack and Infiniti’s Intelligent Dual Clutch Control system with a 7-speed automatic transmission.
2. What’s the fuel economy? EPA ratings are approximately 27 mpg city / 32 mpg highway / 29 mpg combined, which is impressive for a luxury sedan of this size and power.
3. Is it available in AWD? No, the M Hybrid is rear-wheel drive only. If you need AWD, you’d have to consider the non-hybrid M37x.
4. How does it compare to the non-hybrid M37? The M Hybrid offers better fuel economy (29 vs 20 mpg combined) while providing more power (360 vs 330 hp). However, it costs more upfront and has slightly less trunk space due to the battery.
5. What’s the reliability like? Infiniti hybrids have a mixed reliability record. The hybrid system components can be expensive to repair outside of warranty. Battery longevity is generally good, but replacement costs are high if needed.
6. How much trunk space is lost to the battery? The M Hybrid has 10.5 cubic feet of trunk space compared to 14.9 cubic feet in the non-hybrid M37, a reduction of about 30%.
7. What luxury features are included? Standard features include leather seats, dual-zone climate control, Bluetooth, navigation, backup camera, and a premium audio system. Options include adaptive cruise control, lane departure warning, and heated/cooled seats.
8. Can it run on electric power alone? Yes, but only at low speeds (under 62 mph) and for limited distances (about 1.2 miles). It’s primarily designed as a parallel hybrid for efficiency rather than extended EV mode.
9. What’s the typical used price range? As of 2025-2026, you can find 2013-2014 M Hybrids ranging from approximately $12,000-$20,000 depending on mileage, condition, and location.
10. What should I look for when buying used? Check hybrid battery health, transmission smoothness (the dual-clutch system can be problematic), service records for regular maintenance, and test all electronic systems. A pre-purchase inspection by an Infiniti specialist is highly recommended.
Final Verdict
The 2013–2014 Infiniti M Hybrid offers rare performance-oriented hybrid luxury at an affordable used price. Buyers who understand the hybrid system, budget for battery aging, and verify recall and software updates can enjoy a fast, refined sedan with a unique character. Those seeking lower long-term risk may prefer conventional gasoline competitors.
