Theory Of Operation

WARNING: This page is about a different variant/trim than selected.

The purpose of this diagnostic is to check if the engine has trouble relative to the engine torque signal. This signal is sent by the PCM to the TCM. If the TCM receives "Engine limp home bit", a DTC will be set. When the engine is in Engine Limp Home state, the engine RPM may be limited. This DTC is considered informational because the actual error is related to a fault in the Powertrain Control Module.

This DTC may set due to unauthorized software or hardware that can alter the torque characteristics of the engine or torque related signals to the PCM. Some hardware may not set a flag that it was installed if removed prior to receiving the vehicle for service. Always inspect the vehicle for evidence of unauthorized software or hardware.

Devices which may alter the Accelerator Pedal Position (APPS) Signal.
Devices which may alter the Manifold Absolute Pressure (MAP) Signal.
Devices which alter the Throttle Position Sensor (TPS) signal.

NOTE:

This list is in no way all inclusive, it just lists some known signals that may be modified in the pursuit of enhanced engine performance that may cause this DTC to set. Some devices may be not be detectable if removed. If an unauthorized device is suspected, check for items such as hook and loop tape or two sided tape that may be attached to mount a device, disturbed electrical connectors at sensors and correct wire routing to components.