Multiplex Integrated Control Unit

DTC Troubleshooting: U0155

DTC U0155:

MICU Lost Communication With Gauge Control Module

NOTE: If you are troubleshooting multiple DTCs, be sure to follow 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. Wait for at least 6 seconds.

4. Check for DTCs with the HDS.

Is DTC U0155 indicated?

YES -

Go to step 5.

NO -

Intermittent failure, the system is OK at this time. Check for loose or poor connections between the MICU and the gauge control module.

5. Measure the voltage between body ground and gauge control module 32P connector terminals No. 16 and No. 32 individually.





Is there battery voltage?

YES -

Go to step 7.

NO -

Go to step 6.

6. Check the No. 23(10 A) fuse in the under-hood fuse/relay box and the No. 10(7.5 A) fuse in the under-dash fuse/relay box.

Are the fuses OK?

YES -

Repair an open or high resistance in the No. 23(10 A) and/or No. 10(7.5 A) fuse circuit.

NO -

Replace the fuse(s). If the fuse blows again, repair a short to ground in the No. 23(10 A) and/or No. 10 (7.5 A) fuse circuit.

7. Measure the voltage between body ground and gauge control module 32P connector terminals No. 13, No. 17, and No. 18 individually.





Is there less than 0.2 V?

YES -

Go to step 8.

NO -

Repair an open or high resistance in the ground wire or poor ground (G401).

8. Turn the ignition switch to LOCK (0).

9. Disconnect the gauge control module 32P connector.

10. Disconnect under-dash fuse/relay box connector T (34P).

11. Check for continuity between gauge control module 32P connector terminals No. 19 and No. 20 and under-dash fuse/relay box connector T (34P) terminals No. 29 and No. 12 respectively.





Is there continuity?

YES -

Replace the gauge control module Service and Repair.

NO -

Repair an open or poor connection in the B-CAN wire between the MICU and the gauge control module.