OBD-II Code Library

Crankshaft Position Sensor "A" Circuit Malfunction

P0335 means the ECM is not receiving a valid signal from the crankshaft position sensor (CKP).

Random / Multiple Cylinder Misfire Detected

P0300 means the ECM detected misfires in more than one cylinder, or misfires that jump randomly between cylinders.

Cylinder 1 Misfire Detected

P0301 means the ECM detected a misfire specifically in cylinder 1.

Cylinder 2 Misfire Detected

P0302 means a misfire was detected specifically in cylinder 2.

Cylinder 3 Misfire Detected

P0303 indicates a misfire in cylinder 3.

Cylinder 4 Misfire Detected

P0304 indicates a misfire in cylinder 4.

"A" Camshaft Position Over-Advanced or System Performance (Bank 1)

P0011 means the Bank 1 intake camshaft is in a more advanced position than the ECM commanded, or cannot return to the base position.

Crankshaft Position — Camshaft Position Correlation (Bank 1, Sensor A)

P0016 means the ECM detected that the crankshaft and Bank 1 intake camshaft positions are out of sync.

Camshaft Position Sensor "A" Circuit (Bank 1)

P0340 means the ECM is not receiving a valid signal from the Bank 1 camshaft position sensor.

Vehicle Speed Sensor Malfunction

P0500 means the ECM is not receiving a valid signal from the vehicle speed sensor (VSS).

Transmission Control System (MIL Request)

P0700 is not a standalone fault — it is a signal from the Transmission Control Module (TCM) requesting that the powertrain MIL (check engine light) be turned on.

System Too Lean (Bank 1)

P0171 means the engine control module (ECM) has detected that the air-fuel mixture in Bank 1 is too lean — there is too much air or too little fuel.

System Too Rich (Bank 1)

P0172 means the ECM detected that Bank 1's air-fuel mixture is too rich — too much fuel or too little air.

System Too Lean (Bank 2)

P0174 is identical to P0171 but applies to Bank 2 — the opposite bank from cylinder 1 on V6 and V8 engines.

Catalyst System Efficiency Below Threshold (Bank 1)

P0420 means the catalytic converter on Bank 1 is not reducing exhaust emissions efficiently enough.

Catalyst System Efficiency Below Threshold (Bank 2)

P0430 is identical to P0420 but applies to Bank 2 — the opposite bank of the engine.

Knock Sensor 1 Circuit Malfunction (Bank 1)

P0325 means the knock sensor circuit on Bank 1 is not operating correctly.

Exhaust Gas Recirculation Flow Insufficient Detected

P0401 means the EGR (Exhaust Gas Recirculation) system is not flowing enough exhaust gas back into the intake manifold.

Idle Control System Malfunction

P0505 means the idle air control (IAC) system is not maintaining the target idle speed.

Evaporative Emission Control System — Small Leak Detected

P0442 means the ECM detected a small leak (less than 0.

Evaporative Emission Control System — Large Leak Detected

P0455 means the EVAP system has a significant leak — larger than 0.

Evaporative Emission Control System — Very Small Leak Detected

P0456 indicates a very small EVAP leak — under 0.

Coolant Temperature Below Thermostat Regulating Temperature

P0128 means the engine coolant is not reaching its target operating temperature (typically 195–200°F) within the expected time window.

Evaporative Emission Control System Malfunction

P0440 is a general EVAP system code indicating a malfunction without specifying a particular leak size.

Evaporative Emission Control System Vent Control Circuit Malfunction

P0446 means the EVAP vent control valve circuit is not functioning correctly.