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DTC P1633: ELECTRIC THROTTLE CONTROL SYSTEM (ETCS) CIRCUIT ECM MALFUNCTION Lexus GS II

CAUTIONIf 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.

Circuit Description

ETCS is composed of throttle control motor, electromagnetic clutch, Throttle Position (TP) sensor, accelerator 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 causes are

  1. ECM.