Limp mode: Codes, Causes & Fixes

P0299 Powertrain The turbo or supercharger isn't building the boost pressure the engine computer is asking for. Moderate P0606 Powertrain The engine computer failed its own internal self-test – check its power and grounds before… Moderate P0700 Powertrain The transmission computer found a fault and asked for the check engine light – read the TCM… Moderate P2002 Powertrain The ECU thinks the diesel particulate filter isn't trapping soot properly — or it can't measure… Moderate 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

P0471 Powertrain The exhaust backpressure reading doesn't match what the computer expects; the sensor tube… Moderate P0472 Powertrain Exhaust backpressure sensor signal near zero volts: dead sensor, grounded wire or lost 5 V… Moderate P0500 Powertrain The engine computer lost its vehicle speed signal – speedometer, shifting and cruise control… Moderate P0563 Powertrain The engine computer sees too much supply voltage – usually an overcharging alternator cooking… Moderate P0600 Powertrain The engine computer lost a dedicated data link to another module, most often the transmission… Moderate P0601 Powertrain The engine computer's stored software failed its checksum test at start-up – usually a reflash… Moderate P0605 Powertrain The memory holding the engine computer's program failed its integrity test – try one reflash… Moderate P0606 Powertrain The engine computer failed its own internal self-test – check its power and grounds before… Moderate P0607 Powertrain A general internal performance check in the engine computer failed – supply, grounds… Moderate P061B Powertrain The ECM's safety monitor disagreed with its own engine torque calculation – often bad input… Moderate P0638 Powertrain The electronic throttle or diesel intake throttle can't reach its commanded angle, often due… Moderate P0641 Powertrain The PCM's shared 5-volt supply 'A' is missing or out of range – often one shorted sensor… High P0642 Powertrain The PCM's 5-volt supply 'A' is being pulled below spec, usually by a short to ground in one… High P0651 Powertrain The PCM's second 5-volt sensor supply is out of range – usually a pedal, throttle or pressure… Moderate P0700 Powertrain The transmission computer found a fault and asked for the check engine light – read the TCM… Moderate P0707 Powertrain The range sensor signal voltage is below its lowest valid value – usually a short to ground… Moderate P0711 Powertrain The fluid temperature reading doesn't behave like real fluid – it warms too slowly, too fast… Moderate P0712 Powertrain The fluid temperature signal voltage is too low, so the computer thinks the fluid is extremely… Moderate P0715 Powertrain The transmission computer has lost a reliable input-shaft speed signal, so shifts get harsh… Moderate P0717 Powertrain The input speed sensor reports zero while the engine runs and the car moves – the signal… Moderate P0720 Powertrain Electrical fault in the output shaft speed signal – shift timing and sometimes the speedometer… Moderate P0722 Powertrain The output speed sensor sends nothing while the car moves – shifting and often the speedometer… Moderate P0730 Powertrain The transmission computer sees input and output shaft speeds that don't fit the gear it… High P0732 Powertrain Second gear isn't holding: the input-to-output speed ratio in 2nd is outside the expected range. Moderate P0746 Powertrain Solenoid A doesn't control pressure as commanded: harsh or soft shifts, or limp mode. Moderate P0748 Powertrain The TCM detected an electrical fault (open, short or wrong current) in pressure control… Moderate P0750 Powertrain The transmission computer sees a fault in shift solenoid A or its circuit and can't use it… Moderate P0751 Powertrain Solenoid A is wired fine but its valve isn't doing its job, so gears are missing – often stuck… High P0753 Powertrain The control circuit for shift solenoid A reads open, shorted or out of range – an electrical… Moderate P0755 Powertrain The TCM detects an electrical problem with shift solenoid B, the second on/off shift valve. Moderate