01/08/2026
Jeep Grand Cherokee SRT HELLCAT – Fault Codes
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ENGINE & SUPERCHARGER
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P0300 – Random/Multiple Cylinder Misfire
Cause: Worn spark plugs, faulty ignition coils, injector issue
Solution: Replace spark plugs, coils, inspect injectors
P0301–P0308 – Cylinder Misfire Detected
Cause: Coil or injector failure on specific cylinder
Solution: Replace faulty coil or injector
P0101 – Mass Air Flow Sensor Range/Performance
Cause: Dirty or faulty MAF sensor
Solution: Clean or replace MAF sensor
P0128 – Coolant Thermostat Below Regulating Temperature
Cause: Thermostat stuck open
Solution: Replace thermostat
P0234 – Engine Overboost Condition
Cause: Supercharger boost control issue
Solution: Inspect boost control system, bypass valve
P0299 – Turbo/Supercharger Underboost
Cause: Boost leak or supercharger belt issue
Solution: Check intake pipes, belt, and bypass valve
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FUEL SYSTEM
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P0171 – System Too Lean (Bank 1)
Cause: Vacuum leak or fuel delivery problem
Solution: Inspect intake hoses, fuel pressure
P0172 – System Too Rich (Bank 1)
Cause: Faulty injector or sensor
Solution: Inspect injectors and fuel sensors
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EXHAUST & EMISSIONS
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P0420 – Catalyst System Efficiency Below Threshold
Cause: Catalytic converter or O2 sensor failure
Solution: Test O2 sensors, replace catalytic converter
P0130 – O2 Sensor Circuit Malfunction
Cause: Faulty oxygen sensor
Solution: Replace O2 sensor
P0440 – EVAP System Malfunction
Cause: EVAP leak or loose fuel cap
Solution: Inspect EVAP system and fuel cap
P0456 – Small EVAP Leak Detected
Cause: Cracked hose or purge valve issue
Solution: Repair leak, replace purge valve
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TRANSMISSION (8HP)
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P0700 – Transmission Control System Malfunction
Cause: Transmission fault detected
Solution: Scan TCM for detailed codes
P0731 – Gear 1 Incorrect Ratio
Cause: Low transmission fluid or internal wear
Solution: Check fluid level and transmission condition
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ABS / TRACTION / AWD
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C0035 – Left Front Wheel Speed Sensor
Cause: Dirty or damaged sensor
Solution: Clean or replace wheel speed sensor
C121C – Torque Request Denied
Cause: ABS or traction control fault
Solution: Diagnose ABS and traction system
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ELECTRICAL & COMMUNICATION
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U0100 – Lost Communication With ECM/PCM
Cause: CAN bus wiring or ECU issue
Solution: Inspect wiring and ECU connections
U0140 – Lost Communication With BCM
Cause: Body Control Module communication fault
Solution: Check CAN wiring, update BC
