Rough idle: Codes, Causes & Fixes

P0101 Powertrain The MAF sensor's airflow reading doesn't match what the engine computer expects… Low P0171 Powertrain The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees… Moderate P0172 Powertrain The engine computer is pulling as much fuel as it's allowed on bank 1 and the mixture is still… Moderate P0174 Powertrain The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction… Moderate P0300 Powertrain The engine computer sees misfires that jump between cylinders or hit several cylinders at once. High P0302 Powertrain Cylinder 2 keeps misfiring. On inline engines it's a middle cylinder, so rule out coolant… Moderate

P0008 Powertrain Camshaft timing on bank 1 has drifted from the crankshaft. Often a stretched timing chain. Moderate P0010 Powertrain The PCM found an electrical fault in the intake cam phaser solenoid circuit on bank 1, not… Low P0011 Powertrain The bank 1 intake cam sits further advanced than the PCM asked for, usually an oil or control… Moderate P0015 Powertrain The bank 1 exhaust cam sits later than commanded; a stretched chain or stuck exhaust phaser… Moderate P0016 Powertrain The bank 1 intake cam and the crankshaft are out of step, most often from a stretched or jumped… High P0017 Powertrain The bank 1 exhaust cam signal doesn't line up with the crankshaft; think chain, exhaust phaser… Moderate P0018 Powertrain The bank 2 intake cam is out of step with the crankshaft on a V or boxer engine; chain wear… High P0019 Powertrain The bank 2 exhaust cam signal doesn't match the crankshaft; chain, bank 2 exhaust phaser… Moderate P0020 Powertrain Electrical fault in the bank 2 intake cam solenoid circuit on a V or boxer engine; bank 2… Low P0021 Powertrain The bank 2 intake cam is more advanced than commanded or slow to respond; compare it with bank… Moderate P0024 Powertrain The bank 2 exhaust cam stays too far advanced or reacts too slowly; check the valve, the oil… Moderate P0026 Powertrain The oil-operated valve control on the bank 1 intake side isn't responding as commanded. Check… Low P0028 Powertrain A bank 2 valve lift solenoid didn't produce the expected result; low or old oil is the most… Low P0068 Powertrain The airflow the engine measures doesn't match what the throttle opening says it should be. Moderate 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 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 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 P0108 Powertrain The MAP signal is pinned near 5 volts, so the PCM sees impossibly high manifold pressure even… Moderate P0115 Powertrain The ECU can't get a usable coolant temperature signal; the sensor circuit is open, shorted… Low P0117 Powertrain The coolant temperature signal is pinned near zero volts, which the PCM reads as an impossibly… Low P0118 Powertrain The coolant sensor signal sits near 5 volts, so the PCM thinks the engine is frozen solid… Low P0120 Powertrain The throttle position signal dropped out or glitched, so the PCM no longer trusts the throttle… Moderate P0121 Powertrain The throttle position reading is electrically valid but doesn't agree with engine load, airflow… Moderate