Speed & Idle Control Trouble Codes: List & Fixes

P0505 Powertrain The engine computer can't hold idle speed where it wants it – usually a dirty or sticking idle… Low P0507 Powertrain The engine idles faster than the computer's target – most often extra air is sneaking… Low

P0500 Powertrain The engine computer lost its vehicle speed signal – speedometer, shifting and cruise control… Moderate P0501 Powertrain A speed signal exists, but it doesn't match what engine rpm, gear and other sensors say the car… Low P0503 Powertrain The speed signal jumps, spikes or reads impossibly high – usually electrical noise or a loose… Low P0504 Powertrain The two contacts in the brake pedal switch disagree on whether you're braking; check the pedal… Moderate P0505 Powertrain The engine computer can't hold idle speed where it wants it – usually a dirty or sticking idle… Low P0506 Powertrain The engine idles below the computer's target even with idle air opened up – usually a gummed-up… Low P0507 Powertrain The engine idles faster than the computer's target – most often extra air is sneaking… Low P0508 Powertrain The idle air control circuit reads low voltage – a shorted valve coil, lost power feed or wire… Low P0509 Powertrain The ECU sees too much voltage on the idle air valve circuit, so it has lost control of the idle… Low P0511 Powertrain The computer can't drive the idle air control valve properly – typically an open winding… Low P0520 Powertrain The engine computer gets a signal from the oil pressure sensor or switch that makes no… Moderate P0521 Powertrain The oil pressure reading doesn't fit engine speed and temperature – a drifting sensor or truly… High P0522 Powertrain The oil pressure signal is below what a working sensor can produce – usually wiring… Moderate P0523 Powertrain The oil pressure signal is stuck near 5 volts, above any real pressure – almost always sensor… Low P0524 Powertrain Measured oil pressure fell below the safe minimum. Stop the engine now and check the oil before… Critical 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 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 P0638 Powertrain The electronic throttle or diesel intake throttle can't reach its commanded angle, often due… Moderate P1295 Hyundai · Powertrain Hyundai's engine computer no longer trusts the electronic throttle and has cut power as… High P1506 Ford · Powertrain Ford's idle speed stays above target even though the PCM has closed the idle air valve as far… Low P1507 Ford · Powertrain Ford's idle keeps dropping below target even with the idle air valve commanded wide open, often… Low P1516 Chevrolet · Powertrain The electronic throttle didn't move to where the computer commanded, so the engine drops into… Moderate P1519 Honda · Powertrain The PCM found a fault in the idle air control valve (IACV) circuit on a Honda with a cable… Moderate