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HOMESERVICE MANUALSTOYOTA2004MATRIX XR, FWD, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 599 (LIGHTING SYSTEM - DIAGNOSIS)DTC B1268: BACK-UP COMMUNICATION BUS MALFUNCTIONINSPECTION 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. INSPECT DRIVER SIDE JUNCTION BLOCK (COMMUNICATION CIRCUIT) 
    1. Disconnect the connector "D5" "D3" of driver side J/B ECU.
    2. Check the DTC.

      OK: 

      Code B1268 is not output. 

    1. OK: REPLACE DRIVER SIDE JUNCTION BLOCK 
    2. NG: GO TO NEXT STEP 
  2. INSPECT LUGGAGE ROOM JUNCTION BLOCK ASSEMBLY (COMMUNICATION CIRCUIT) 
    1. Disconnect the connector "R13" of luggage room J/B ECU.
    2. Check the DTC.

      OK: 

      Code B1288 is not output. 

    1. OK: REPLACE LUGGAGE ROOM JUNCTION BLOCK ASSEMBLY 
    2. NG: GO TO NEXT STEP 
  3. INSPECT TURN SIGNAL SWITCH ASSEMBLY (COMMUNICATION CIRCUIT) 
    1. Disconnect the connector "C11" of combination switch ECU.
    2. Check the DTC.

      OK: 

      Code B1268 is not output. 

    1. OK: REPLACE TURN SIGNAL SWITCH ASSEMBLY 
    2. NG: GO TO NEXT STEP 
  4. CHECK HARNESS AND CONNECTOR (BACK-UP COMMUNICATION BUS) 
    1. Disconnect the connector of "D3" "D5" of driver side J/B and "R13" of luggage room J/B.
    2. Check continuity between terminals BU- of driver side J/B ECU and BUBS of luggage room J/B ECU.

      OK: 

      There Is No Continuity In Wire Harness 

    HINT:

    If there is SHORT in wire harness, please repair it.

    1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. OK: GO TO NEXT STEP 
  5. CHECK HARNESS AND CONNECTOR (BACK-UP COMMUNICATION BUS) 
    1. Disconnect the connector of "D3" "D5" of driver side J/B and "C11" of combination switch ECU.
    2. Check continuity between terminals HEAD of driver side J/B ECU and HEAD of combination switch ECU.
    3. Check continuity between terminals BU+ of driver side J/B ECU and TXI of combination switch ECU.

      OK: 

      There Is No Continuity In Wire Harness 

    HINT:

    If there is SHORT in wire harness, please repair it.

    1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 
    2. OK: REPLACE LUGGAGE ROOM JUNCTION BLOCK ASSEMBLY 
RENDER: 1.0x

NO RELATED

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When to See a Mechanic

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

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • 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.