B1235

Control System DTCs

DTC Troubleshooting: B1235 - (42)

DTC B1235 or DTC indicator 42 : A Problem in the Air Mix Control Motor Circuit, Linkage, Door, or Motor

1. Problem verification:

Problem verification
-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 with the HDS or the climate control unit How To Troubleshoot The Climate Control System.

-4. Check for DTCs.

Is DTC B1235 or 42 indicated?
-YES- Go to step 2.
-NO- Intermittent failure. Check for loose wires or poor connections in the air mix control motor circuit.

2. Open wire check (M-HOT, M-COOL lines):

Open wire check (M-HOT, M-COOL lines)
-1. Turn the ignition switch to LOCK (0).

-2. Disconnect the following connectors.





-3. Check for continuity between test points 1 and 2 respectively.














Is there continuity?
-YES- The M-HOT and M-COOL wires are OK. Go to step 3.
-NO- Repair an open in the wire(s) between the climate control unit and the air mix control motor.

3. Shorted wire check (M-HOT, M-COOL lines):

Shorted wire check (M-HOT, M-COOL lines)
-1. Check for continuity between test points 1 and 2 individually.














Is there continuity?
-YES- Repair a short to body ground in the wire(s) between the climate control unit and the air mix control motor.
-NO- The M-HOT and M-COOL wires are OK. Go to step 4.

4. Air mix control motor check:

Air mix control motor check
-1. Test the air mix control motor Air Mix Control Motor Test.

Is the air mix control motor OK?
-YES- Replace the climate control unit . Service and Repair
-NO- Replace the air mix control motor Air Mix Control Motor Removal and Installation, or repair the air mix control linkage or door.