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Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 182 (Multiplex Communication System) >> Diagnostic Tests >> DTC B1212/12: Front Passenger Door Ecu Communication Stop >> Diagnostic Procedure

Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Lexus RX 300 and 2002 Lexus RX 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check the front passenger door ECU. Check if the front passenger door window glass can auto up. With this inspection, the front passenger door ECU can be diagnosed if it works normally or not. If the results are OK, go to the next step. If the results are not good, replace the front passenger door ECU. See DRIVER DOOR ECU & FRONT PASSENGER DOOR ECU  under REMOVAL & INSTALLATION.
  2. Check the wiring harness. Disconnect the connector E8 of the ECM, passenger door ECU and R13 of the rear right door ECU. See WIRING DIAGRAMS .
    1. Check continuity between terminal No. 11 (MPX1) of the ECM and terminal No. 11 (MPX2) of the passenger door ECU. See CONNECTOR IDENTIFICATION .
    2. Check the continuity between terminal No. 10 (MPX1) of the passenger door ECU and terminal No. 4 (MPX2) of the rear right door ECU.
  3. The results are OK if there is continuity in the wiring harness of both step (a) and (b), or either step (a) or (b). If there is an open in the wiring harness of either step (a) or (b), repair it. If the results are OK, replace the passenger door ECU. See DRIVER DOOR ECU & FRONT PASSENGER DOOR ECU  under REMOVAL & INSTALLATION. If the results are not good, repair or replace the wiring harness.
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