| CAUTION | If Engine Control Module (ECM) replacement is instructed in following test, always ensure ECM electrical connectors and ground circuits are okay. If either are defective, repair and repeat testing to confirm ECM malfunction. On models equipped with engine immobilizer, if ECM is replaced, ECM must be programmed with proper ignition key code for engine immobilizer system. For programming procedures, see COMPUTER RELEARN PROCEDURES - TOYOTA article in GENERAL INFORMATION, or appropriate ENGINE IMMOBILIZER SYSTEMS article in ACCESSORIES & EQUIPMENT. |
Circuit Description
Accelerator pedal position sensor is located on throttle body and uses 2 sensors which monitor accelerator position. Accelerator pedal position sensor delivers input signals to VPA1 and VPA2 terminals at ECM in proportion to throttle opening. ECM uses input signals for controlling the throttle control motor. DTC is set when ECM determines voltage is out of range on VPA1 or VPA2 circuits between accelerator pedal position sensor and ECM. ECM determines the current opening angle of the accelerator pedal from these inputs and controls the throttle motor based on these signals. Possible causes are
- Accelerator pedal position sensor circuit is open or shorted.
- Defective accelerator pedal position sensor.
- Defective ECM.
Diagnostic Aids
Note. Refer to DIAGNOSTIC AIDS in DTC P2120 repair procedure.