Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSTOYOTA2004MATRIX XR, FWD, STANDARDREPAIR AND DIAGNOSISEXTERNAL PAGESDIFFERENT CARSECTION 207 (MULTIPLEX COMMUNICATION SYSTEM)DIAGNOSTIC TESTSDTC B1271: COMBINATION METER ECU COMMUNICATION STOPDIAGNOSTIC PROCEDURE
2004 Toyota Matrix XR, FWD, Standard
Diagnostic Procedure
2004 Toyota Matrix XR, FWD, StandardSECTION Diagnostic Procedure
WARNING: This page is about a different car, the 2003 Lexus IS 300 and 2002 Lexus IS 300. However, it is still accessible from the selected car via links, so may be relevant.
- Check the combination meter ECU. Start the engine and check that the speedometer and tachometer operate normally. With this inspection, the combination meter 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 faulty combination meter ECU. See INSTRUMENT PANEL article in ACCESSORIES & EQUIPMENT.
- Disconnect connector A13 of the A/C ECU, connector C9 of the combination meter ECU, connector B6 of the body ECU and connector T6 of the anti-theft ECU, if equipped. See Fig 1.
- Check the continuity between connector A13 terminal 10 (MPX+) of the A/C ECU and connector C9 terminal 21 (MPX-) of the combination meter ECU. See CONNECTOR IDENTIFICATIONΒ .
- On vehicles without anti-theft system, check continuity between connector C9 terminal 9 (MPX+) of the combination meter and connector B6 terminal 5 (MPX2) of the body ECU. On vehicles with anti-theft system, check continuity between connector C9 terminal 20 (MPX+) of the combination meter and connector T6 terminal 8 (MPX2) of the anti-theft ECU.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- β’ You smell fuel, burning insulation, or see smoke.
- β’ Brakes feel soft, pull hard to one side, or make grinding noises.
- β’ The engine overheats, stalls repeatedly, or misfires under load.
- β’ You are missing required tools, torque specs, or safe lifting equipment.
- β’ You are not confident in the next step or safety outcome.