Car won't start: Codes, Causes & Fixes

P0335 Powertrain The engine computer lost the crankshaft position signal. Expect stalling or a crank-no-start. High P0340 Powertrain The computer lost the camshaft signal on bank 1. Expect long cranking, less power… Moderate P0562 Powertrain The engine computer sees too little supply voltage – usually a charging, battery or ground… Moderate P0606 Powertrain The engine computer failed its own internal self-test – check its power and grounds before… Moderate U0073 Network A module saw so many errors on CAN bus A that it shut off its own transmitter. High U0100 Network Another module stopped hearing from the engine computer on the CAN network. High

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 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 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 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 P0641 Powertrain The PCM's shared 5-volt supply 'A' is missing or out of range – often one shorted sensor… High P0642 Powertrain The PCM's 5-volt supply 'A' is being pulled below spec, usually by a short to ground in one… High P0685 Powertrain The engine computer can't switch its own main power relay – open coil, blown fuse or broken… High P0686 Powertrain The main relay control line is being pulled to ground – usually a shorted relay coil… Moderate P0687 Powertrain The main relay control line sits at battery voltage – the relay may never switch on or never… Moderate P069E Chevrolet · Powertrain The fuel pump control module stored its own fault and asked the engine computer for the check… Moderate P0705 Powertrain The computer can't make sense of the gear selector position signal – P, R, N, D may be misread. Moderate P0706 Powertrain The range sensor works electrically, but its reading doesn't match where the lever and gears… Moderate P0707 Powertrain The range sensor signal voltage is below its lowest valid value – usually a short to ground… Moderate P0A0F Powertrain The hybrid system spun the gas engine with its motor-generator to start it, but the engine… High P0A1F Powertrain The module that manages the high-voltage battery failed its self-check or reports implausible… Moderate P0A94 Powertrain A hybrid voltage converter isn't delivering the voltage it should – on Toyotas, the boost… High P0A95 Powertrain The main fuse in the high-voltage battery circuit has opened or its circuit reads open… Critical P0AA6 Powertrain High voltage is leaking toward the car body somewhere – an insulation fault that must be found… High P0AFA Powertrain Total high-voltage battery voltage dropped below the minimum the system allows, so power… High P1233 Ford · Powertrain The Ford PCM lost the status signal from the fuel pump driver module, so fuel pump control… Moderate P1260 Ford · Powertrain Ford's Passive Anti-Theft System didn't accept the key, so the PCM shut off fuel and the engine… Moderate P1289 Ford · Powertrain The CHT sensor signal on your Ford is stuck near 5 volts, which the PCM reads as an impossibly… Moderate