OBD-II Diagnostic Library
Every code decoded. Learn exactly what your check engine light means, what tests your mechanic must perform, and whether it's safe to keep driving.
Electrical
P0101
MAF Sensor Range Performance
P0102
MAF Sensor Low Input
P0103
MAF Sensor High Input
P0113
Intake Air Temp High Input
P0117
Engine Coolant Temp Low Input
P0118
Engine Coolant Temp High Input
P0120
Throttle Position Sensor Malfunction
P0122
Throttle Position Sensor Low Input
P0123
Throttle Position Sensor High Input
P0220
Throttle Position Sensor Circuit
P0335
UrgentCrankshaft Position Sensor Malfunction
P0340
Camshaft Position Sensor Malfunction
P0460
Fuel Level Sensor Malfunction
P0463
Fuel Level Sensor High Input
P0480
Cooling Fan Control Circuit
P0481
Cooling Fan Circuit 2
P0500
Vehicle Speed Sensor Malfunction
P0505
Idle Air Control System Malfunction
P0506
Idle Speed Lower Than Expected
P0507
Idle Speed Higher Than Expected
P0520
Engine Oil Pressure Sensor Malfunction
P0521
Engine Oil Pressure Range Performance
P0522
UrgentEngine Oil Pressure Low
P0523
Engine Oil Pressure High
P0562
System Voltage Low
P0563
System Voltage High
P0600
Serial Communication Link Malfunction
P0606
UrgentECM Processor Fault
P0641
Sensor Reference Voltage A Circuit
P0650
Malfunction Indicator Lamp Circuit
Emissions
P0128
Coolant Thermostat Below Regulating Temperature
P0130
O2 Sensor Circuit Malfunction
P0133
O2 Sensor Slow Response
P0135
O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 1
P0141
O2 Sensor Heater Circuit Malfunction Bank 1 Sensor 2
P0150
O2 Sensor Circuit Bank 2
P0155
O2 Sensor Heater Circuit Bank 2
P0161
O2 Sensor Heater Circuit Bank 2 Sensor 2
P0401
EGR Flow Insufficient Detected
P0410
Secondary Air Injection System Malfunction
P0420
Catalyst Efficiency Below Threshold Bank 1
P0421
Warm Up Catalyst Efficiency Below Threshold
P0430
Catalyst Efficiency Below Threshold Bank 2
P0431
Warm Up Catalyst Efficiency Bank 2
P0440
EVAP System Malfunction
P0441
EVAP Incorrect Purge Flow
P0442
EVAP System Small Leak Detected
P0443
EVAP Purge Control Valve Circuit
P0445
EVAP Purge Valve High Input
P0446
EVAP Vent Control Circuit
P0452
Fuel Tank Pressure Sensor Low Input
P0453
Fuel Tank Pressure Sensor High Input
P0455
EVAP System Large Leak
P0456
EVAP System Very Small Leak
P0457
EVAP Leak Gas Cap Loose
P0496
EVAP Flow During Non-Purge Condition
Engine Misfire
P0217
UrgentEngine Overheat Condition
P0300
UrgentRandom/Multiple Cylinder Misfire Detected
P0301
UrgentCylinder 1 Misfire
P0302
UrgentCylinder 2 Misfire
P0303
UrgentCylinder 3 Misfire
P0304
UrgentCylinder 4 Misfire
P0305
UrgentCylinder 5 Misfire
P0306
UrgentCylinder 6 Misfire
P0325
Knock Sensor Malfunction
P0351
UrgentIgnition Coil Circuit Cylinder 1
P0352
UrgentIgnition Coil Circuit Cylinder 2
P0353
UrgentIgnition Coil Circuit Cylinder 3
P0354
UrgentIgnition Coil Circuit Cylinder 4
Fuel System
P0171
System Too Lean Bank 1
P0172
System Too Rich Bank 1
P0174
System Too Lean Bank 2
P0200
Injector Circuit Malfunction
P0201
Injector Circuit Cylinder 1
P0202
Injector Circuit Cylinder 2
P0203
Injector Circuit Cylinder 3
P0204
Injector Circuit Cylinder 4
P0230
UrgentFuel Pump Primary Circuit
P0231
UrgentFuel Pump Low Voltage
P0232
Fuel Pump High Voltage
Transmission
P0700
Transmission Control System Malfunction
P0705
Transmission Range Sensor Circuit
P0715
Input Speed Sensor Malfunction
P0720
Output Speed Sensor Malfunction
P0730
Incorrect Gear Ratio
P0740
Torque Converter Clutch Circuit
P0741
Torque Converter Clutch Performance
P0750
Shift Solenoid A Malfunction
P0755
Shift Solenoid B Malfunction
P0760
Shift Solenoid C Malfunction
P0770
Shift Solenoid E Malfunction
P0780
Shift Malfunction
P0790
Normal/Performance Switch Circuit
P0800
Transfer Case Control System
P0850
Park/Neutral Switch Input
P0868
UrgentTransmission Fluid Pressure Low