HVAC

DTC Troubleshooting: U0155

DTC U0155:

HVAC Control Unit Lost Communication with Gauge Control Module

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. Do the self-diagnostic function with the HDS.

4. Check for DTCs.

Is DTC U0155 indicated?

YES -

Go to step 5.

NO -

The system is OK at this time. Check for loose wires or poor connections on the gauge control module and HVAC control unit circuit.�

5. Select UNIT INFORMATION in the BODY ELECTRICAL menu.

6. Select CONNECTED UNITS in the UNIT INFORMATION menu.

Is the gauge control module detected?

YES -

Substitute a known-good HVAC control unit, and recheck. If the symptom/indication goes away, replace the original HVAC control unit HVAC Control Unit Removal/Installation.�

NO -

Go to step 7.

7. Disconnect the gauge control module 32P connector.

8. Disconnect HVAC control unit connector A (24P).

9. Check for continuity between the following terminals of the gauge control module 32P connector and HVAC control unit connector A (24P).









Is there continuity?

YES -

Go to gauge control module input test Gauge Control Module Input Test.�

NO -

Repair an open in the wire between the HVAC control unit and the gauge control module.�