Check engine light on: Codes, Causes & Fixes

P0174 Powertrain The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction… Moderate P0420 Powertrain The bank 1 catalytic converter no longer stores enough oxygen to clean the exhaust properly. Low P0101 Powertrain The MAF sensor's airflow reading doesn't match what the engine computer expects… Low P0113 Powertrain The intake air temperature signal is stuck at maximum voltage, which usually means an open… Low P0135 Powertrain The heater inside the upstream oxygen sensor on bank 1 isn't working or its circuit is faulty. Low P0171 Powertrain The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees… 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