| CAUTION | If ECM replacement is instructed in following testing, always ensure ECM harness connector and ground circuit are okay. If either are suspect, repair and repeat testing to confirm ECM malfunction. If ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES article in GENERAL INFORMATION. |
Circuit Description
The accelerator pedal position sensor is a 2 variable resistor sensor that monitors throttle opening and accelerator pedal position sensor malfunction. ECM controls throttle motor and electromagnetic clutch based on signal from accelerator pedal position sensor. If DTC P1121 is set, ECM shuts down power to throttle control motor and electromagnetic clutch.
DTC P1121 is set when ECM consistently detects difference between VPA and VPA2 circuits out of tolerance for 2 seconds. Possible cause is; faulty accelerator pedal position sensor.
Diagnostic Aids
Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.