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DTC P1633: ECM MALFUNCTION (ELECTRONIC THROTTLE CONTROL SYSTEM CIRCUIT) Lexus LX J100

Note. EFI fuse may also be referred to as ECD fuse.

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. 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. Possible cause is

  1. Defective ECM.