B1556

DTC Troubleshooting: B1556

DTC B1556:

Automatic Lighting Control Unit Lost Communication With the MICU (MICU Message)

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

1. Clear the DTCs with the HDS.

2. Turn the ignition switch to LOCK (0), and then back to ON (II).

3. Check for DTCs with the HDS.

Are DTCs B1157, B1806 also indicated with B1556 ?

YES -

Go to MICU input test. Exterior Lights (MICU) Input Test�

NO -

Go to step 4.

4. Measure the voltage between automatic lighting control unit 14P connector terminals No. 1 and No. 8, and terminals No. 7 and No. 9 respectively.





Is there battery voltage?

YES -

Replace automatic lighting control unit Service and Repair.�

NO -

Repair an open in the wire, a blown No. 36 (10 A) fuse or No. 10 (7.5 A) fuse in the driver's under-dash fuse/relay box, or poor ground (G401).�