HVAC Control Unit

Control System DTCs

HVAC DTC Troubleshooting: 4

DTC indicator 4 : An Open in the Mode Control Motor Circuit

1. Problem verification:

Problem verification
-1. Turn the ignition switch to LOCK (0), and then back to ON (II).

-2. Do the Self-Diagnostic Function with the HVAC control unit.

-3. Check for DTCs.

Is DTC 4 indicated?
-YES- Go to step 2.
-NO- Intermittent failure. Check for loose wires or poor connections on the mode control motor circuit.

2. DTC check:

DTC check
-1. Check for DTCs.

Is DTC 1 or 7 indicated?
-YES- Repair an open in the wire between the HVAC control unit and the mode control motor.
-NO- Go to step 3.

3. Open wire check (MODE-P line):

Open wire check (MODE-P line)
-1. Turn the ignition switch to LOCK (0).

-2. Connect terminals A and B with a jumper wire.

















-3. Turn the ignition switch to ON (II).

-4. Do the Self-Diagnostic Function with the HVAC control unit How to Troubleshoot the Heating and A/C Systems (Manual A/C).

-5. Check for DTCs.

Is DTC 4 indicated?
-YES- Repair an open in the wire between the HVAC control unit and the mode control motor.
-NO- The MODE-P wire is OK. Replace the mode control motor Mode Control Motor Test.