Check engine light on: Codes, Causes & Fixes

P0302 Powertrain Cylinder 2 keeps misfiring. On inline engines it's a middle cylinder, so rule out coolant… Moderate P0174 Powertrain The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction… Moderate P0011 Powertrain The bank 1 intake cam sits further advanced than the PCM asked for, usually an oil or control… Moderate P0301 Powertrain Cylinder 1 is repeatedly failing to fire. The cause is almost always its coil, plug, injector… Moderate P0021 Powertrain The bank 2 intake cam is more advanced than commanded or slow to respond; compare it with bank… Moderate P0014 Powertrain The bank 1 exhaust cam won't follow its target and stays too far advanced; think oil, valve… Moderate

P052E Powertrain The crankcase ventilation regulator isn't controlling crankcase pressure properly – often… Moderate P0532 Powertrain The A/C pressure sensor reads too low – often a low refrigerant charge, sometimes a wiring… Low P0533 Powertrain The A/C high-side pressure reads too high – often a dead cooling fan, clogged condenser… Low P0550 Powertrain The engine computer lost a believable power steering pressure switch signal; idle may dip when… Low P0560 Powertrain The engine computer saw its supply voltage missing or out of range – check fuses and feeds… Moderate P0561 Powertrain System voltage jumps up and down instead of holding steady – often loose terminals… Low P0562 Powertrain The engine computer sees too little supply voltage – usually a charging, battery or ground… Moderate P0563 Powertrain The engine computer sees too much supply voltage – usually an overcharging alternator cooking… Moderate P0571 Powertrain The engine computer doesn't trust the brake pedal switch signal – cruise control usually stops… Low P0572 Powertrain The PCM never sees the brake pedal pressed – brake lights may be out and the car may not shift… Moderate P0573 Powertrain The PCM thinks the brake pedal is always pressed – brake lights stay on, often from a missing… Moderate P0597 Powertrain The electrically heated thermostat's heater circuit is open, so the ECU can't open it early… Low P0600 Powertrain The engine computer lost a dedicated data link to another module, most often the transmission… Moderate P0601 Powertrain The engine computer's stored software failed its checksum test at start-up – usually a reflash… Moderate P0602 Powertrain The engine computer has no valid or complete software – typical after a module swap or a failed… Moderate P0603 Powertrain The engine computer lost its learned memory – usually after a battery disconnect or a bad… Low P0604 Powertrain The engine computer's working memory failed a read/write test – rarely a software issue, often… Moderate P0605 Powertrain The memory holding the engine computer's program failed its integrity test – try one reflash… Moderate P0606 Powertrain The engine computer failed its own internal self-test – check its power and grounds before… Moderate P0607 Powertrain A general internal performance check in the engine computer failed – supply, grounds… Moderate P0610 Powertrain The engine computer's vehicle configuration is missing or doesn't match the car – usually after… Low P061B Powertrain The ECM's safety monitor disagreed with its own engine torque calculation – often bad input… Moderate P0620 Powertrain The engine computer found a fault in the wire or signal it uses to command alternator output. Moderate P0621 Powertrain A fault in the alternator's 'L' circuit – the line behind the charge light or the ECM's turn-on… Moderate P0622 Powertrain The alternator's field control or field feedback circuit is faulty – output may drop out… Moderate P0625 Powertrain The PCM sees the alternator's field-monitor signal stuck low – usually the regulator, its plug… Moderate P0626 Powertrain The alternator reports a field signal stuck at or near full output – battery, alternator… Moderate P0627 Powertrain The PCM's fuel pump command line has no complete circuit – a dead relay coil, open wire, fuse… Moderate P0628 Powertrain The fuel pump control wire is pulled toward ground – a chafed wire, shorted relay coil or wet… Moderate P0629 Powertrain Battery voltage is leaking into the fuel pump control line – a short, corrosion bridge… Moderate