GM Service Manual Online
For 1990-2009 cars only

When certain throttle actuator control module (TAC) system DTCs are set , the TAC system will default to a REDUCED ENGINE POWER Mode and the PCM will turn ON the REDUCED ENGINE POWER lamp. The PCM controls the lamp by grounding the control circuit with an internal switch called a driver. The engine RPM will drop to 1100 RPM and the vehicle will operate with reduced acceleration and speed.