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.
DTC B1255: Combination Switch Control Unit Lost Communication With MICU
2004 Acura TL AutomaticSECTION DTC B1255: Combination Switch Control Unit Lost Communication With MICU
NOTE:
If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN system diagnosis test mode A (see
TROUBLESHOOTING - B-CAN SYSTEM DIAGNOSIS TEST MODE A ).
- Clear the DTCs with the HDS.
- Turn the ignition switch OFF, and then back ON (II).
- Check for DTCs with the HDS.
Is DTC B1255 indicated?
- YES - Go to step 4.
- NO - Intermittent failure, MICU is OK at this time. Check for loose or poor connection at combination switch control unit connector (8P), and at under-dash fuse/relay box connector X (39P). If the connections are good, check the battery condition (see BATTERY TEST ) and the charging system.
- Check for DTCs with the HDS.
Are DTCs B1055, B1157 and B1806 indicated?
- YES - Go to MICU INPUT TEST .
- NO - Replace the combination switch control unit.
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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.