Rough idle: Codes, Causes & Fixes

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 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 P0302 Powertrain Cylinder 2 keeps misfiring. On inline engines it's a middle cylinder, so rule out coolant… Moderate

P0350 Powertrain The shared coil feed, ignition module or coil wiring is faulty. Often set with several… Moderate P0351 Powertrain The engine computer found an electrical fault in coil A, the coil that fires cylinder 1 on most… Moderate P0352 Powertrain Coil B, normally on cylinder 2, has a circuit fault. Where cylinder 2 sits depends… Moderate P0353 Powertrain The circuit for coil C, which fires cylinder 3, failed its electrical check. Wiring is a big… Moderate P0354 Powertrain Coil D, normally the one on cylinder 4, failed its circuit check. It often shows up right after… Moderate P0355 Powertrain Coil E, the coil for cylinder 5, has an electrical fault. Only engines with five or more… Moderate P0356 Powertrain The coil F circuit for cylinder 6 failed its check. On inline sixes it's the coil… Moderate P0357 Powertrain Coil G, which fires cylinder 7 on V8s, has an electrical fault. On GM trucks it sits by… Moderate P0358 Powertrain Coil H, for cylinder 8, has an electrical fault. On nearly every V8 it's the hardest coil… Moderate P0366 Powertrain Bank 1 exhaust cam signal is out of position: chain stretch, a sticky exhaust phaser… Moderate P0402 Powertrain More exhaust is being recirculated than the ECU asked for, usually because the EGR valve won't… Moderate P052E Powertrain The crankcase ventilation regulator isn't controlling crankcase pressure properly – often… Moderate P0560 Powertrain The engine computer saw its supply voltage missing or out of range – check fuses and feeds… Moderate P0604 Powertrain The engine computer's working memory failed a read/write test – rarely a software issue, often… Moderate P0626 Powertrain The alternator reports a field signal stuck at or near full output – battery, alternator… Moderate P0638 Powertrain The electronic throttle or diesel intake throttle can't reach its commanded angle, often due… Moderate P06DD Powertrain The ECM commanded an oil pressure change and the measured pressure didn't respond – check… High P0742 Powertrain The converter lockup clutch stays applied when it should be released, which can stall… High P1295 Hyundai · Powertrain Hyundai's engine computer no longer trusts the electronic throttle and has cut power as… High P1300 Toyota · Powertrain Toyota's ECM fires ignition coil No. 1 but gets no confirmation pulse (IGF) back from its… Moderate P1305 Toyota · Powertrain The igniter in Toyota coil No. 2 stops confirming its sparks, often only once the engine is hot. Moderate P1310 Toyota · Powertrain No spark confirmation from one Toyota coil: No. 3 on four-cylinders, but a different coil… Moderate P1320 Nissan · Powertrain The Nissan ECM isn't seeing the ignition primary signal it expects while the engine cranks… Moderate P1336 Ford · Powertrain The Ford PCM sees the cam and crank signals out of step, usually from a mistimed or worn cam… Moderate P1340 Volkswagen · Powertrain The cam signal no longer lines up with the crank signal – often a jumped belt or stretched… High P1345 Chevrolet · Powertrain The cam signal is out of step with the crank signal; on Vortec engines usually a mis-set… Moderate P1346 Toyota · Powertrain Toyota's ECM sees the intake cam signal in the wrong place relative to the crankshaft signal. Moderate P1349 Toyota · Powertrain Toyota's VVT-i system isn't moving the intake camshaft to the position the ECM is asking for. Moderate P1354 Toyota · Powertrain On a Toyota V6 or V8, the bank 2 intake camshaft isn't reaching the timing the ECM commands. Moderate P1361 Honda · Powertrain The top dead center (TDC) sensor signal keeps dropping out for a moment while the engine… Moderate