GMC OBD Codes: Meaning & Fixes

P0420 Powertrain The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. Low P0300 Powertrain The engine computer sees misfires that jump between cylinders or hit several cylinders at once. High P0700 Powertrain The transmission computer found a fault and asked for the check engine light – read the TCM… Moderate P0128 Powertrain The engine takes too long to warm up, which almost always points to a thermostat stuck open. Low

B0012 Body Airbag firing-loop fault; location depends on the make: passenger dash airbag or, on GM… High B0051 Body SAE: front middle seat buckle sensor fault. On GM vehicles: the airbag module has logged… High C0110 Chassis The GM brake module (EBCM) found a fault in the ABS pump motor circuit and switched ABS off. Moderate P0008 Powertrain Camshaft timing on bank 1 has drifted from the crankshaft. Often a stretched timing chain. Moderate P0011 Powertrain The bank 1 intake cam sits further advanced than the PCM asked for, usually an oil or control… Moderate P0014 Powertrain The bank 1 exhaust cam won't follow its target and stays too far advanced; think oil, valve… Moderate P0016 Powertrain The bank 1 intake cam and the crankshaft are out of step, most often from a stretched or jumped… High P0017 Powertrain The bank 1 exhaust cam signal doesn't line up with the crankshaft; think chain, exhaust phaser… Moderate P0018 Powertrain The bank 2 intake cam is out of step with the crankshaft on a V or boxer engine; chain wear… High P0128 Powertrain The engine takes too long to warm up, which almost always points to a thermostat stuck open. Low P0266 Powertrain The engine computer can't even out cylinder 2 with fuel corrections; its balance rate is past… Moderate P0300 Powertrain The engine computer sees misfires that jump between cylinders or hit several cylinders at once. High P0306 Powertrain Cylinder 6 is misfiring. On an inline-six it's the hot rear cylinder; on GM and Hemi V8s it can… Moderate P0420 Powertrain The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. Low 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 P0700 Powertrain The transmission computer found a fault and asked for the check engine light – read the TCM… Moderate P0711 Powertrain The fluid temperature reading doesn't behave like real fluid – it warms too slowly, too fast… Moderate P0756 Powertrain Solenoid B isn't moving fluid the way the TCM expects – the car may pull away in 3rd or 4th. High P0894 Powertrain The transmission computer measured slip inside the gearbox that shouldn't be there. Clutches… High P2108 Powertrain The throttle control module isn't performing as expected – check its power, data link… Moderate P2138 Powertrain The two sensors in the gas pedal report different pedal positions, so the PCM limits throttle… Moderate