Check engine light on: Codes, Causes & Fixes

P0174 Powertrain The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction… Moderate P0420 Powertrain The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. Low P0101 Powertrain The MAF sensor's airflow reading doesn't match what the engine computer expects… Low P0113 Powertrain The intake air temperature signal is stuck at maximum voltage, which usually means an open… Low P0135 Powertrain The heater inside the upstream oxygen sensor on bank 1 isn't working or its circuit is faulty. Low P0171 Powertrain The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees… Moderate

P0045 Powertrain The engine computer sees an open or shorted circuit to the solenoid that controls turbo boost. Moderate P0046 Powertrain The boost control solenoid circuit is intact, but boost doesn't follow what the solenoid… Moderate P0050 Powertrain The heater circuit of the upstream sensor on bank 2 – the side without cylinder 1 – is out… Low P0051 Powertrain The bank 2 upstream sensor heater draws no current: open element, lost feed or broken wire. Low P0056 Powertrain The heater circuit of the sensor behind the bank 2 converter is erratic – typical… Minor P0057 Powertrain The heater behind the bank 2 converter draws no current – open element or cut, torn… Minor P0068 Powertrain The airflow the engine measures doesn't match what the throttle opening says it should be. Moderate P0069 Powertrain With the engine stopped, the manifold pressure and barometric pressure readings don't agree. Low P0075 Powertrain The intake cam timing solenoid on bank 1 has an open, short or bad driver circuit, so cam… Low P0081 Powertrain Electrical fault in the bank 2 intake cam solenoid on a V6 or V8; only one cylinder bank loses… Low P0087 Powertrain Measured fuel pressure has dropped well below what the engine computer is asking for. High P0088 Powertrain Rail pressure is running well above the value the engine computer is commanding. Moderate P0089 Powertrain The fuel pressure regulator is getting its commands but pressure isn't responding the way it… Moderate P0090 Powertrain The engine computer sees an electrical fault in the wiring or coil of the fuel pressure control… Moderate P0093 Powertrain Rail pressure is dropping faster than injection explains: fuel may be escaping. Stop and check… Critical P0100 Powertrain The PCM sees an electrical fault in the MAF sensor circuit: signal missing, erratic or not… Low P0101 Powertrain The MAF sensor's airflow reading doesn't match what the engine computer expects… Low P0102 Powertrain The MAF signal is too weak for the PCM to accept, so it treats the circuit as dead… Moderate P0103 Powertrain The MAF claims more airflow than the engine could possibly take in, usually from a short… Low P0105 Powertrain The PCM lost a usable signal from the manifold pressure sensor: dropouts, noise or values it… Moderate P0106 Powertrain The MAP sensor works electrically, but its pressure reading doesn't fit what the engine… Low P0107 Powertrain The MAP signal has fallen to almost zero volts, usually from a lost 5-volt reference or an open… Moderate P0108 Powertrain The MAP signal is pinned near 5 volts, so the PCM sees impossibly high manifold pressure even… Moderate P0110 Powertrain The PCM can't get a stable, believable signal from the intake air temperature sensor circuit. Low P0111 Powertrain The IAT reading is electrically fine but doesn't match the other temperatures the ECU knows. Minor P0112 Powertrain The IAT signal is near zero volts, so the PCM believes the intake air is scorching hot, usually… Low P0113 Powertrain The intake air temperature signal is stuck at maximum voltage, which usually means an open… Low P0114 Powertrain The IAT signal keeps dropping out or jumping for a moment and coming back, a sign of a loose… Minor P0115 Powertrain The ECU can't get a usable coolant temperature signal; the sensor circuit is open, shorted… Low P0116 Powertrain The coolant temperature signal is electrically fine but doesn't behave the way the PCM expects. Low