| 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
ETCS is composed of throttle control motor, electromagnetic clutch, Throttle Position (TP) sensor, accelerator pedal position sensor, ECM and throttle body. If DTC P1633 is set, ECM shuts down power to throttle control motor and electromagnetic clutch. DTC P1633 is set when ECM malfunctions. Possible cause is; faulty ECM.
Diagnostic Aids
Using scan tool, read freeze frame data. Freeze frame records engine conditions when malfunction is detected.