B1556

DTC B1556: Automatic Lighting Control Unit Lost Communication with Multiplex Integrated Control Unit (MICU Message)

Touring model

NOTE: If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A.

1. Clear the DTCs with the HDS.
2. Turn the ignition switch OFF, and then back ON (II).
3. Check for DTCs with the HDS.

Are DTCs B1055, B1106, B1157, B1255, B1355, B1J556, B1806, B1955, B2005, and B2055 indicated?

YES - Go to MICU input test. MICU Input Test

NO - Go to step 4.




4. Check for voltage between the No. 1 and No. 8 terminals, and No. 7 and No. 9 terminals.

Is there battery voltage?

YES - Faulty automatic lighting control unit.

NO - Repair an open in the wire, a blown No. 30 (10 A) fuse or No. 21 (7.5 A) fuse in the driver's under-dash fuse/box, or poor ground (G501).