DTC Troubleshooting: U0155
DTC U0155:
 Heater Control Unit Lost Communication with Gauge Control Module
  1. Clear the DTC with the HDS.
  1. Turn the ignition switch to LOCK (0) and then to ON (II).
  1. 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 the heater control unit circuit.■
  1. Select UNIT INFORMATION in the BODY ELECTRICAL menu.
  1. Select CONNECTED UNIT in the UNIT INFORMATION menu.
Is the gauge control module detected?
YES -
Substitute a known-good heater control unit, and recheck. If the symptom/indication goes away, replace the original heater control unit. ■
NO -
Go to Step 7 .
  1. Disconnect the gauge control module 32P connector.
  1. Disconnect heater control unit connector B (12P).
  1. Check for continuity between the following terminals of the gauge control module 32P connector, and heater control unit connector B (12P).
    12P:
    32P:
    No. 1
    No. 24
    No. 2
    No. 23

Is there continuity?
YES -
NO -
Repair open in the wire between the heater control unit and the gauge control module.■