Chevrolet OBD Codes: Meaning & Fixes

P0420 Powertrain The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. Low C0035 Chassis The ABS module lost a valid signal from the driver-side front wheel speed sensor. Moderate P0171 Powertrain The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees… Moderate P0299 Powertrain The turbo or supercharger isn't building the boost pressure the engine computer is asking for. Moderate P0300 Powertrain The engine computer sees misfires that jump between cylinders or hit several cylinders at once. High P0304 Powertrain Cylinder 4 is misfiring. Its end or rear position makes water, oil and intake leaks common… Moderate

P0216 Powertrain The ECU can't control or confirm injection timing, usually on a diesel with an electronic… High P0266 Powertrain The engine computer can't even out cylinder 2 with fuel corrections; its balance rate is past… Moderate P0299 Powertrain The turbo or supercharger isn't building the boost pressure the engine computer is asking for. Moderate P0300 Powertrain The engine computer sees misfires that jump between cylinders or hit several cylinders at once. High P0304 Powertrain Cylinder 4 is misfiring. Its end or rear position makes water, oil and intake leaks common… Moderate P0305 Powertrain Cylinder 5 is misfiring. First job: work out which bank it sits on, because that decides what… Moderate P0306 Powertrain Cylinder 6 is misfiring. On an inline-six it's the hot rear cylinder; on GM and Hemi V8s it can… Moderate P0307 Powertrain Cylinder 7 is misfiring. On GM and Hemi V8s it's a cylinder-deactivation cylinder, so check… Moderate P0308 Powertrain Cylinder 8 is misfiring. It's a rear V8 cylinder against the firewall, so its plug is often… Moderate P0325 Powertrain The computer isn't getting a usable signal from knock sensor 1, so it pulls timing to protect… Low P0327 Powertrain Knock sensor 1's signal is too weak or pulled to ground: usually wiring, water or a loose… Low P0330 Powertrain The second knock sensor, usually the one for the bank without cylinder 1, has a circuit fault. Low P0335 Powertrain The engine computer lost the crankshaft position signal. Expect stalling or a crank-no-start. High P0336 Powertrain Crank signal present but implausible: damaged teeth, a slipped balancer ring or debris confuse… Moderate P0346 Powertrain Bank 2's cam signal arrives out of position. On V6/V8s that often means a bank 2 chain, guide… Moderate P0350 Powertrain The shared coil feed, ignition module or coil wiring is faulty. Often set with several… Moderate P0403 Powertrain The ECU found an electrical fault in the circuit that drives the EGR solenoid or electric EGR… Low P0404 Powertrain The EGR valve isn't moving to the position the ECU commands, or its position report doesn't… Low P0410 Powertrain The cold-start air pump system that helps heat the catalytic converter didn't pass its… Low P0412 Powertrain The ECU found an open or short in the circuit of the valve that routes air from the pump into… Low P0418 Powertrain The ECU sees a fault in the relay circuit that switches the secondary air pump on and off. Low P0420 Powertrain The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. Low P0430 Powertrain The bank 2 converter on a V6, V8 or split-exhaust engine isn't cleaning the exhaust well enough. Low P0446 Powertrain The canister vent valve isn't doing what the ECU commands — electrically or because the vent… Minor P0449 Powertrain Electrical fault on the canister vent solenoid circuit, a staple on GM trucks with the solenoid… Low P0452 Powertrain The tank pressure sensor signal is stuck near 0 volts, lower than the sensor can physically… Minor P0455 Powertrain The fuel vapor system can't hold vacuum at all — check the gas cap first, then hoses and valves. Low P0458 Powertrain The purge valve control line reads too low: lost power feed, open coil or a wire shorted… Low P0461 Powertrain The fuel level reading doesn't change the way fuel use says it should – usually a worn or stuck… Low P0463 Powertrain Fuel level signal reads like an open circuit – most often a corroded tank-top connector… Low