Limp mode: Codes, Causes & Fixes
Limp mode (also called reduced power or fail-safe mode) is the vehicle protecting itself: the engine or transmission computer limits power, RPM or gear selection after detecting a fault. Typical triggers are throttle pedal or throttle body faults, turbo boost problems and transmission sensor or solenoid faults. Drive gently to a safe place or a shop; restarting may clear it temporarily, but the stored codes show the real cause.
165Codes
3.3Average severity
28%High or critical
4%DIY-friendly
Severity distribution
Most viewed
P0299
Powertrain
The turbo or supercharger isn't building the boost pressure the engine computer is asking for.
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
P0606
Powertrain
The engine computer failed its own internal self-test – check its power and grounds before…
Moderate
All codes (165)
P0269
Powertrain
Cylinder 3 isn't pulling its weight, or is pulling too hard, and the fuel correction for it…
Moderate
P0275
Powertrain
The fuel correction for cylinder 5 is past its limit. Only engines with five or more cylinders…
Moderate
P0299
Powertrain
The turbo or supercharger isn't building the boost pressure the engine computer is asking for.
Moderate
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
P0610
Powertrain
The engine computer's vehicle configuration is missing or doesn't match the car – usually after…
Low
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