Zone Overcurrent - (MTC)

ZONE OVERCURRENT - MTC

For a complete wiring diagram Consult Diagrams/Electrical

- When Monitored:
When actuator movement is requested.

- Set Condition:
This DTC will set if the A/C Heater Control detects an excessive current draw on any of the door driver circuits while attempting to drive the Zone Door Actuator. Only one overcurrent DTC can set per ignition cycle.





Diagnostic Test

1. VERIFY DTC IS ACTIVE
Turn the ignition on.
With the scan tool, erase DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
With the scan tool, read DTCs.
Does the scan tool display this DTC as active?

Yes

- Go To2

No

- The condition that caused this symptom is currently not present. Check for an intermittent condition by inspecting the related wiring harness for chafed, pierced, pinched, and partially broken wires. Also, inspect the related connectors for broken, bent, pushed out, spread, corroded, or contaminated terminals. Repair as necessary.
- Perform the BODY VERIFICATION TEST - VER 1. Body Verification Test.

2. CHECK FOR PROPER ZONE DOOR ACTUATOR OPERATION
Turn the ignition on.
Actuate the Zone Door Actuator.
Does the Zone Door Actuator operate normally?

Yes

- Go To4

No

- Go To3

3. CHECK FOR ACTIVE: ZONE DOOR CIRCUIT SHORTED TO GROUND
With the scan tool, erase DTCs.
Turn the ignition off, wait 10 seconds, and turn the ignition on.
Actuate the Zone Door Actuator.
With the scan tool, read DTCs.
Does the scan tool display active: ZONE DOOR CIRCUIT SHORTED TO GROUND?

Yes

- Follow the diagnostics for ZONE DOOR CIRCUIT SHORTED TO GROUND.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Go To4

4. CHECK FOR 12 VOLTS TO THE ZONE DOOR ACTUATOR




Turn the ignition off.
Disconnect the Zone Door Actuator harness connector.
Turn the ignition on.
Actuate the Zone Door Actuator.
Using a volt meter measure the voltage on the (C34) Zone Door Driver (A) circuit in the Zone Door Actuator harness connector.
Does the volt meter read 12 volts?

Yes

- Go To5

No

- Go To6

5. CHECK FOR A BLOCKAGE STALLING THE ZONE DOOR ACTUATOR
Turn the ignition off.
Remove the Zone Door Actuator from the HVAC housing assembly.
Look for anything on the Zone Door Actuator and in the HVAC housing that is physically preventing Zone Door Actuator operation.
Is anything physically preventing Zone Door Actuator operation?

Yes

- Repair as necessary. Also, check Zone Door Actuator for proper operation. Reinstall, or replace the Zone Door Actuator as necessary .

No

- Replace the Zone Door Actuator.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

6. CHECK FOR CHAFING IN THE (C34) ZONE DOOR DRIVER (A) CIRCUIT
Turn the ignition off.
Check the (C34) Zone Door Driver (A) circuit for wire chafing.
Is any wire chafing present?

Yes

- Repair the wire chafing on the (C34) Zone Door Driver (A) circuit.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.

No

- Replace the A/C Heater Control Head.
- Perform BODY VERIFICATION TEST - VER 1. Body Verification Test.