Diagnostic Aids

Scan tester displays APP No. 1 position in volts, and should display .45-.95 volt with throttle closed and ignition on or engine at idle. Voltage should increase at a steady rate as throttle is moved toward WOT. Also, 90 percent pedal travel is acceptable for correct APP operation. Monitor APP No. 1 sensor while applying accelerator pedal with engine off and ignition on. Display should vary from about .74 volt with throttle closed, to about 3.7 volts with throttle at WOT. If ground circuit is open or APP signal circuit is shorted to voltage, DTC 21 will set.

Fig 1: DTC 21 Schematic ("G" Series) APP No. 1 Circuit High (Models With PCM)

Fig 2: DTC 21 Schematic ("P" Series) APP No. 1 Circuit High (Models With PCM)

Fig 3: DTC 21 Flow Chart (All Models) APP No. 1 Circuit High (Models With PCM)