Check engine light on: Codes, Causes & Fixes

P0302 Powertrain Cylinder 2 keeps misfiring. On inline engines it's a middle cylinder, so rule out coolant… Moderate P0174 Powertrain The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction… Moderate P0011 Powertrain The bank 1 intake cam sits further advanced than the PCM asked for, usually an oil or control… Moderate P0301 Powertrain Cylinder 1 is repeatedly failing to fire. The cause is almost always its coil, plug, injector… Moderate P0021 Powertrain The bank 2 intake cam is more advanced than commanded or slow to respond; compare it with bank… Moderate P0014 Powertrain The bank 1 exhaust cam won't follow its target and stays too far advanced; think oil, valve… Moderate

P0A7E Powertrain The high-voltage battery got too hot. A clogged cooling intake or dirty fan is the usual cause. Moderate P0A7F Powertrain The battery computer has calculated that the whole high-voltage pack has worn past its usable… Moderate P0A80 Powertrain The hybrid system sees weak or unbalanced modules in the high-voltage battery and flags… Moderate P0A93 Powertrain The inverter's separate coolant loop isn't carrying heat away – usually a dead electric… High 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 P1101 Chevrolet · Powertrain GM's engine computer found that measured airflow doesn't agree with what it expects. Low P1128 Jeep · Powertrain Your Jeep's PCM never switched bank 1 from preset fueling to O2-sensor feedback after… Low P1128 Volkswagen · Powertrain VW's part-load fuel adaptation has maxed out adding fuel on bank 1 – the engine runs lean as… Moderate P1129 Jeep · Powertrain The PCM couldn't switch bank 2 of your Jeep's V6 or V8 into oxygen-sensor-controlled fueling… Low P1131 Ford · Powertrain Ford's front O2 sensor on bank 1 stays lean even after the PCM has added all the fuel it… Low P1132 Ford · Powertrain Ford's front O2 sensor on bank 1 keeps reading rich even though the PCM has pulled out as much… Low P1133 Chevrolet · Powertrain The front oxygen sensor on bank 1 isn't flipping between rich and lean often enough during GM's… Low P1134 Chevrolet · Powertrain Bank 1's front O2 sensor reacts much faster in one direction (rich or lean) than the other. Low P1135 Toyota · Powertrain The heater inside Toyota's upstream air/fuel ratio sensor is drawing too much or too little… Low P1136 Volkswagen · Powertrain At idle the VW computer is adding the maximum fixed amount of fuel on bank 1 – a classic vacuum… Low P1137 Volkswagen · Powertrain At idle the VW computer is pulling out as much fuel as it's allowed on bank 1 and the mix… Low P1151 Ford · Powertrain On a Ford V6 or V8, the front O2 sensor on the bank 2 side stays lean and never switches back… Low P1152 Ford · Powertrain On a Ford V6 or V8, the bank 2 front O2 sensor sticks on rich even after the PCM leaned that… Low P1153 Chevrolet · Powertrain The front O2 sensor on the passenger-side bank of a Chevy V6/V8 isn't cycling rich-lean often… Low P1154 Chevrolet · Powertrain On a Chevy V6/V8, the bank 2 front O2 sensor rises and falls at clearly different speeds. Low P1155 Toyota · Powertrain The heater in the front-bank air/fuel ratio sensor of a Toyota V6 or V8 is out of its current… Low P1157 Honda · Powertrain The signal lines of Honda's upstream air/fuel ratio sensor read too high, usually an open… Low P1166 Honda · Powertrain The circuit that powers the heater in Honda's upstream A/F sensor is open, shorted or unpowered. Low P1167 Honda · Powertrain The upstream A/F sensor heater is powered but isn't drawing the current or heating the sensor… Low P1217 Nissan · Powertrain Nissan's ECM saw engine coolant get hotter than it should, usually because the radiator fan… Critical P1233 Ford · Powertrain The Ford PCM lost the status signal from the fuel pump driver module, so fuel pump control… Moderate P1259 Honda · Powertrain The PCM saw the VTEC solenoid or VTEC oil pressure switch misbehave on an older Honda VTEC… Moderate