Climate Control Unit

DTC Troubleshooting: U1281

DTC U1281:

Climate Control Unit Lost Communication with MICU (WIPSW 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. Do the self-diagnostic function with the HDS.

4. Check the DTCs.

Is DTC U1281 indicated?

YES -

Go to step 5.

NO -

The system is OK at this time. Check for loose wires or poor connections on the MICU and climate control unit circuit.

5. Select B-CAN Control Units Information in the BODY ELECTRICAL menu.

6. Select Check Connected Control Units in the B-CAN Control Units Information menu.

Is the MICU detected?

YES -

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

NO -

Go to step 7.

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

8. Disconnect climate control unit connector A (36P).

9. Check for continuity between the following terminals of climate control unit connector A (36P) and under-dash fuse/relay box connector T (34P).









Is there continuity?

YES -

Go to the MICU input test MICU And Door Multiplex Control Unit Input Test.

NO -

Repair an open in the wire(s) between the MICU and the climate control unit.