B1555

DTC B1555: Automatic Lighting Control Unit Lost Communication with Combination Switch Control Unit (AUTOLT 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.

Is DTC B1555 indicated?

YES - Go to combination switch control unit input test. Combination Switch Control Unit Input Test

NO - Go to step 4.




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