| 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
Throttle valve opening angle is detected by Throttle Position (TP) sensor and sends a signal to ECM. ECM then uses this signal to control throttle control motor which opens and closes throttle valve in response to driving conditions. If DTC P1129 is present, ECM turns off power to throttle motor and magnetic clutch and throttle valve is fully closed by return spring. When this occurs, opening angle of throttle valve is controlled by accelerator pedal by means of a throttle cable. DTC is set when throttle opening angle varies greatly from target throttle opening angle. Possible causes are
- Throttle control motor circuit is open.
- Defective throttle body.
- Defective ECM.
Diagnostic Aids
Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.