Manufacturer Code Charts: 7

DTC Troubleshooting: B1231 (7)

DTC B1231 or DTC indicator 7:

An Open in the Evaporator Temperature Sensor Circuit

1. Clear the DTC by turning the ignition switch to LOCK (0), and then turn to ON (II).

2. Operate the A/C control system in several modes.

3. Check for DTCs using the HDS How to Troubleshoot the Heating and A/C Systems or self-diagnostic function How to Troubleshoot the Heating and A/C Systems.

Is DTC B1231 or 7 indicated?

YES -

Go to step 4.

NO -

Intermittent failure, check for loose wires or poor connections on the evaporator temperature sensor circuit.�

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

5. Remove the evaporator temperature sensor Service and Repair and test it Evaporator Temperature Sensor Test.

Does the evaporator temperature sensor test OK?

YES -

Go to step 6.

NO -

Replace the evaporator temperature sensor.�

6. Disconnect A/C control panel connector A (22P).

7. Check for continuity between A/C control panel connector A (22P) terminal No. 14 and evaporator temperature sensor 2P connector terminal No. 1.





Is there continuity?

YES -

Go to step 8.

NO -

Repair an open in the wire between the A/C control panel and the evaporator temperature sensor.�

8. Check for continuity between A/C control panel connector A (22P) terminal No. 3 and evaporator temperature sensor 2P connector terminal No. 2.





Is there continuity?

YES -

Check for loose wire or poor connections at A/C control panel connector A (22P) and at the evaporator temperature sensor 2P connector. If the connections are good, substitute a known-good A/C control panel, and recheck. If the symptom/indication goes away, replace the original A/C control panel A/C Control Panel Removal/Installation.�

NO -

Repair an open in the wire between the A/C control panel and the evaporator temperature sensor.�