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HOMESERVICE MANUALSTOYOTA2004MATRIX XR, FWD, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 605 (MULTIPLEX COMMUNICATION SYSTEM - DIAGNOSIS)DTC B1283: DRIVER SIDE JUNCTION BLOCK ECU COMMUNICATION STOPINSPECTION PROCEDURE
2004 Toyota Matrix XR, FWD, Standard

Inspection Procedure

2004 Toyota Matrix XR, FWD, StandardSECTION Inspection Procedure
WARNING: This page is about a different car, the 2002 Lexus SC 430. However, it is still accessible from the selected car via links, so may be relevant.
  1. CHECK CONTINUITY OF COMMUNICATION LINE 
    1. Check the wire harness among the driver side J/B and front light control ECU and tilt and telescopic ECU.
      Fig 1: Identifying Driver Side J/B & Front Light Control ECU & Tilt & Telescopic ECU
      G03387164Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      1. Disconnect the connectors of the driver side J/B, front light control ECU and tilt and telescopic ECU.
      2. Check the continuity between terminal D4-7 (MPX2) of the driver side J/B vehicle's side connector and terminal T8-7 (MPX1) of the tilt and telescopic ECU vehicle's side connector.

        Standard: Continuity 

      3. Check the continuity between terminal D2-13 (MPX1) of the driver side J/B vehicle's side connector and terminal 6 (MPX2) of the front light control ECU vehicle's side connector.

        Standard: Continuity 

    1. NG: REPAIR OR REPLACE WIRE HARNESS OR CONNECTOR 
    2. OK: GO TO NEXT STEP 
  2. CHECK MULTIPLEX NETWORK BODY ECU 
    1. Inspect the ECU power source input.
      1. Disconnect the J/B connector D4.
      2. Check the voltage between each terminal of the J/B vehicle's side connector.
      Fig 2: Identifying J/B Connector D4
      G03387165Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

    Standard: 

    SPECIFIED CONDITION

    Tester connection Condition Specified condition
    D4-5 (MPX-B) - Body ground Constant 10 - 14 V
    1. NG: REPAIR OR REPLACE FUSE OR WIRE HARNESS AND CONNECTOR 
    2. OK: GO TO NEXT STEP 
  3. CHECK MULTIPLEX NETWORK BODY ECU 
    1. Inspect the ECU body ground.
      1. Disconnect the ECU connectors D4 and 2G.
        2. Fig 3: Identifying ECU Connectors D4
        G03387166Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
RENDER: 1.0x

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Stop DIY work and contact a certified mechanic immediately if any of the following apply:

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  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.