Check engine light on: Codes, Causes & Fixes

P0135 Powertrain The heater inside the upstream oxygen sensor on bank 1 isn't working or its circuit is faulty. Low P0174 Powertrain The cylinder bank without cylinder 1 is running lean even with the maximum fuel correction… Moderate P0113 Powertrain The intake air temperature signal is stuck at maximum voltage, which usually means an open… Low P0171 Powertrain The engine computer is adding the maximum extra fuel it's allowed on bank 1 and still sees… Moderate P0172 Powertrain The engine computer is pulling as much fuel as it's allowed on bank 1 and the mixture is still… Moderate P0299 Powertrain The turbo or supercharger isn't building the boost pressure the engine computer is asking for. Moderate

P2716 Powertrain The transmission computer sees an open or short in the circuit of pressure control solenoid D. Moderate P2BAC Powertrain EGR has been shut off because of a fault, so NOx is above the limit; fix the EGR code stored… Moderate P3000 Toyota · Powertrain Toyota's hybrid computer flags a fault in the high-voltage battery system and limits hybrid… High P3190 Toyota · Powertrain The hybrid computer asked the gas engine for power and got less than expected. Moderate P3191 Toyota · Powertrain The hybrid system spun the gas engine with its motor-generator, but the engine never fired up. High P3400 Powertrain Cylinder shut-off on bank 1 (AFM, DFM, MDS or VCM) isn't doing what the engine computer… Moderate P3497 Honda · Powertrain Honda's Variable Cylinder Management on the front cylinder bank didn't behave the way the PCM… Moderate U0001 Network A module found the high-speed CAN network itself misbehaving, not just one silent module. High 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 U0101 Network The engine computer and other modules stopped hearing from the transmission control module. High U0102 Network Other modules can't hear the 4WD transfer case module, so 4WD shifting is disabled. Moderate U0105 Network The PCM lost contact with the separate module that fires the injectors, common on diesel… High U0107 Network The engine computer can't reach the module that drives the electronic throttle, so power is cut… High U0109 Network The PCM lost contact with the module that controls fuel pump speed; stalling or no-start can… High U0110 Network The hybrid/EV system lost contact with the module that runs electric drive motor A. Critical U0115 Network Modules lost contact with the second engine computer on vehicles that use two of them. High U0121 Network Other modules stopped receiving data from the ABS module, so ABS and stability control are off. Moderate U0122 Network Other modules lost contact with the stability control computer, so ESC and traction control… Moderate U0140 Network Other modules stopped hearing from the body control module that runs lights, locks, wipers… Moderate U0146 Network The central gateway that links the car's networks went silent, so many modules report errors… Moderate U0155 Network Modules can't reach the instrument cluster, so gauges, warning lights and chimes may go dead. Moderate U0401 Network The engine computer is still on the network, but another module doesn't trust the numbers it's… Moderate U0402 Network The transmission module is online, but the gear, range or torque data it sends doesn't add up. Moderate U0404 Network The electronic shifter reports a lever position the transmission can't trust, so Park may not… High U0415 Network The ABS module is online, but the wheel-speed data it shares looks wrong to the other modules. Moderate U0416 Network Stability-control data (steering angle, yaw rate) failed a plausibility check in another module. Moderate U0418 Network Brake-control data such as pedal position or brake-assist status looks implausible to another… High U0420 Network The electric power steering module is talking, but its steering angle or torque data doesn't… Moderate U1000 Chevrolet · Network A module on an older GM's Class 2 data line couldn't communicate, so modules stopped hearing… Moderate