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Home >> Toyota >> 2004 >> Matrix Base, FWD, Automatic >> Repair and Diagnosis >> External Pages >> Different car >> Section 159 (Multiplex Communication System) >> Diagnostic Tests >> DTC B1293/93: Gateway Ecu Communication Stopped >> Diagnostic Procedure
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Diagnostic Procedure

WARNING: This page is about a different car, the 2003 Lexus GS 430, 2003 Lexus GS 300, 2002 Lexus GS 430, and 2002 Lexus GS 300. However, it is still accessible from the selected car via links, so may be relevant.
  1. Check if the gateway ECU operation is normal. If the results are OK, go to the next step. If the results are not good, replace the gateway ECU. See GATEWAY ECU  under REMOVAL & INSTALLATION.
  2. Check the wiring harness by disconnecting the T5 connector of the tilt and telescopic ECU, A13 of the A/C amplifier ECU, C15 of the steering pad switch and G6 of the gateway ECU. See CONNECTOR IDENTIFICATION .
    1. Check the continuity between terminals MPD1, MPD2 of the gateway ECU and MPX- of the A/C amplifier. See WIRING DIAGRAMS .
    2. Check the continuity between terminals MPD1, MPD2 of the gateway ECU and MPX1 of the tilt and telescopic ECU.
    3. Check the continuity between terminals MPD1, MPD2 of the gateway ECU and MPX1 of the steering pad switch.
    If there is an OPEN in the wiring harness of any terminals, repair it. If there is continuity in the wiring harness of both steps (A) and (B) or (A) and (C), or either (B) or (C), replace the gateway ECU. See GATEWAY ECU  under REMOVAL & INSTALLATION. If there is not continuity as specified, repair or replace the wiring harness. See WIRING DIAGRAMS .
  3. After repairs have been made, perform confirmation test. See CONFIRMATION TEST  under SELF-DIAGNOSTIC SYSTEM.
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