Diagnostic Aids

Scan tool reads APP 1 sensor 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 sensor operation. Scan APP 1 sensor while depressing accelerator pedal with ignition on, engine off. 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 sensor circuit voltages fall within normal ranges. PCM compares pre-scaled voltages (voltages scan tool cannot read). Scan tool reads only output voltages.

Check for intermittent problems (i.e., poor connections, rubbed through wire insulation or broken wire inside its insulation). See appropriate TROUBLE SHOOTING - NO CODES article.