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Home >> GMC >> 1997 >> Forward Control 4.3 W, L35, Automatic >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 10 (Engine Controls - Tests W/Codes - 6.5L Diesel (P Series)) >> Diagnostic Trouble Codes >> DTC P0121 - Accelerator Pedal Position (App) Sensor 1 Circuit Performance >> Diagnostic Aids

Diagnostic Aids

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

Scan tool reads APP 1 position in volts. With throttle closed and ignition on or at idle, voltage should be .45-.95 volt. Voltage should increase at a steady rate as throttle is moved toward Wide Open Throttle (WOT). Ninety percent pedal travel is acceptable for correct APP operation. Scan APP 1 sensor while depressing accelerator pedal with engine off and ignition on. Display should vary from about .74 volt with throttle closed to greater than 3.7 volts with throttle held at WOT.

Diagnostic procedures checks if all APP circuit voltages fall within normal ranges. PCM compares pre-scaled voltages (voltages scan tool can not read). Scan tool reads only output voltages.

Fig 1: Accelerator Pedal Position (APP) Module Diagram
G96D29523