Diagnostic Aids
WARNING: This page is about a different car, the 2002 Saturn Vue. However, it is still accessible from the selected car via links, so may be relevant.
The REDUCED POWER lamp will illuminate and engine will default to the limited throttle authority limp home mode.
Under certain conditions, the ECM will command the engine to shut down.
If any APP or TP sensor DTCs are also set, diagnose those DTCs first. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . Also, if DTCs P1635 or P1639 are set refer to the appropriate DTC. See DTC P1635: 5-VOLT REFERENCE 1 CIRCUIT or DTC P1639: 5-VOLT REFERENCE 2 CIRCUIT .
A skewed TP sensor 1 or 2 can set this DTC. Using the scan tool monitor TP sensor 1 and 2 voltages while varying accelerator pedal position. For approximate readings, see THROTTLE POSITION SENSOR VOLTAGE table under DTC P1120: THROTTLE POSITION SENSOR 1 CIRCUIT.