Car won't start: Codes, Causes & Fixes
First tell the two cases apart: if the engine does not crank at all, the battery, battery terminals, starter or a security/immobilizer lockout are the usual suspects; if it cranks but won't fire, look at fuel delivery, crankshaft position sensor and ignition. Codes such as P0335 (crankshaft sensor) or immobilizer messages narrow it down, but a no-crank fault may leave no code at all. Check battery voltage and terminal connections before anything else.
123Codes
3.2Average severity
28%High or critical
21%DIY-friendly
Severity distribution
Most viewed
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
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
P0606
Powertrain
The engine computer failed its own internal self-test – check its power and grounds before…
Moderate
All codes (123)
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
P0852
Powertrain
The park/neutral input reads too high, usually from an open circuit, unplugged connector or bad…
Low
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
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
P1362
Honda · Powertrain
The PCM gets no signal at all from the top dead center (TDC) sensor; stalling or a no-start…
High
P1391
Jeep · Powertrain
The PCM keeps briefly losing the cam or crank position signal, which can make your Jeep stumble…
Moderate
P1602
Volkswagen · Powertrain
The engine computer saw its constant battery feed drop too low – usually a disconnected, flat…
Low
P1604
Toyota · Powertrain
Toyota's ECM recorded a start that took too long, failed, or died within seconds of firing.
Moderate
P1607
Honda · Powertrain
The Honda engine computer's self-test found a fault inside its own circuitry.
Moderate
P1610
Nissan · Powertrain
After repeated failed immobilizer checks, the Nissan ECM has locked itself and won't let…
Moderate
P1612
Nissan · Powertrain
The Nissan ECM and the immobilizer (IMMU or BCM) couldn't complete their ID exchange, so…
Moderate
P1614
Nissan · Powertrain
The Nissan immobilizer couldn't read the transponder chip in the key, so the engine isn't…
Moderate
P1626
Chevrolet · Powertrain
The engine computer lost the 'OK to fuel' signal from the Chevy anti-theft system, so it may…
Moderate
P1631
Chevrolet · Powertrain
The engine computer received the wrong anti-theft password, so it blocks starting or fuel.
Moderate
P1682
Chevrolet · Powertrain
The engine computer's two ignition power feeds disagree, which can cause stalling or Reduced…
High