OBD-II Fault Code Cross-Reference

HVAC Coolant Pump Control Circuit

Coolant pump failure affecting battery thermal management

Battery Management System Communication Error

BMS to vehicle gateway CAN bus fault

Engine Control System Malfunction

Communication fault between ECM and skid control ECU

Low Battery Positive Voltage

Weak 12V auxiliary battery or alternator failure

Positive Acceleration Sensor Circuit Malfunction

VSC sensor calibration or wiring issue

Drive Inverter Fault

Rear drive unit inverter MOSFET failure

Engine Position System Performance (Bank 1)

Stretched timing chain

Camshaft Position A - Timing Over-Advanced (Bank 1)

Dirty VCT phaser / oil control valve

Camshaft Position Timing Over-Advanced (Bank 1)

OCV (Oil Control Valve) sticking

Crankshaft-Camshaft Position Correlation (Bank 1)

VCT phaser wear or timing chain stretch (3.5L EcoBoost)

Intake Valve Control Solenoid Circuit Range/Performance (Bank 1)

AVCS oil control solenoid failure

Fuel Rail/System Pressure Too Low

CP4 high-pressure fuel pump failure

Engine Coolant Temperature Circuit Low

Electric water pump failure (EA888 common)

Coolant Thermostat Below Regulating Temperature

Stuck-open thermostat or low coolant

System Too Lean (Bank 1)

Dirty MAF sensor, cracked intake boot, PCV valve leak

System Too Lean (Bank 2)

Dirty MAF sensor or cracked intake tube

Turbocharger/Supercharger Overboost Condition

Wastegate actuator sticking, turbo control solenoid

Turbocharger/Supercharger Underboost

Wastegate rattle, cracked charge pipe, degraded turbo

Random/Multiple Cylinder Misfire Detected

Worn ignition coils, fouled spark plugs, carbon buildup

Cylinder 1 Misfire Detected

Carbon-fouled intake valve, worn ignition coil

Camshaft Position Sensor Circuit Intermittent

Camshaft sensor damage from debris

Ignition Coil A Primary/Secondary Circuit

Ignition coil pack failure on cylinder 1

Catalyst System Efficiency Below Threshold (Bank 1)

Aging catalytic converter or degraded rear O2 sensor

Warm Up Catalyst Efficiency Below Threshold (Bank 1)

Catalyst degradation from oil contamination

Catalyst System Efficiency Below Threshold (Bank 2)

Catalytic converter aging or exhaust leak upstream

EVAP System Leak Detected (Medium)

Loose gas cap or cracked EVAP canister hose

EVAP System Very Small Leak Detected

Loose or faulty fuel cap, cracked EVAP line

Electric Coolant Pump Malfunction

Electric coolant pump electronics failure (M256/M264)

Cold Start Rough Idle

Carbon buildup on intake valves disrupting airflow at cold start

Engine Oil Pressure Sensor/Switch Circuit

Oil pressure sensor failure

Engine Oil Pressure Sensor/Switch Range/Performance

Debris from lifter failure clogging oil pickup

Internal Engine Control Module Torque Performance

PCM internal fault or software corruption

Torque Converter Clutch Performance

CVT/9-speed converter wear

Shift Solenoid A

9HP48 solenoid wear

Pressure Control Solenoid B Performance

CVT valve body wear, degraded fluid

Transmission Fluid Pressure Sensor/Switch A Circuit

CVT pressure sensor failure

Hybrid Battery Charger Temperature Sensor Circuit

Battery thermal sensor failure

Hybrid Battery Pack Deterioration

Cell aging, thermal stress

Replace Hybrid Battery Pack

HV battery cell degradation exceeding capacity threshold

Hybrid Battery Isolation Fault

Insulation breakdown in HV battery

HV Battery System Voltage Low

12V battery failure preventing contactor closure

Drive Motor Inverter Performance

Inverter overheating, coolant pump failure

Engine Mount Solenoid Valve Control Circuit

Active engine mount solenoid failure (EA888)

Coolant Pump 2 Switching Off

Electric coolant pump failure

Engine Management System - Knock Sensor Detection

Connecting rod bearing wear (Hyundai/Kia 2.5L)

Fan Speed Performance

Cooling fan module or fan clutch failure

HV Battery Module Voltage Differential

Degraded battery cell module

Intake Manifold Runner Position Sensor (Bank 1)

Intake manifold runner flap motor failure

Reductant Heater A Control Circuit

DEF heater failure in cold climate

SCR NOX Catalyst Efficiency Below Threshold

DEF system degradation

Secondary Air Injection System Switching Valve Stuck Open

Air injection pump and switching valve failure

Diesel Particulate Filter Restriction

DPF clogging from short trips

48V On-Board System Voltage Malfunction

ISG (Integrated Starter Generator) failure on mild-hybrid

Engine Control Module Power Relay Control Circuit

ECM relay or fuse box connection issue

Valve Pause System (Bank 1)

VCM system oil pressure switch failure

Lost Communication With ECM/PCM A

Software instability, gateway module reboot

Vehicle Controller Security System Error

VCSEC module internal fault or 12V battery low