Auxiliary Electrical Heater Module (AEHM)

9040-LOST COMMUNICATION WITH DF

For a complete wiring diagram, Refer to the Wiring Information Electrical Diagrams.

- When Monitored:
Continuously.

- Set Condition:
The Auxiliary Electrical Heater Module (AEHM) detects DF Signal Cable fault.





1. DTC IS ACTIVE
1. Turn the ignition on.
2. With the scan tool, read AEHM DTCs.

Is this DTC active?

Yes

- Go To 2

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. Verification Tests.

2. DF SIGNAL CABLE OPEN
1. Disconnect the A/C Heater Control harness connector.
2. Disconnect the Auxiliary Electrical Heater Module (AEHM) harness connector.
3. Measure the resistance of the DF Signal Cable between the A/C Heater Control harness connector and the Auxiliary Electric Heater Module (AEHM) harness connector.

Does the Ohm meter read open circuit?

Yes

- Repair the DF Signal Cable for an open circuit.
- Perform the BODY VERIFICATION TEST. Verification Tests.

No

- Go To 3

3. AUXILIARY ELECTRICAL HEATER MODULE (AEHM) ECU RESET
1. The Auxiliary Electrical Heater Module (AEHM) is reporting internal errors.
2. Using the scan tool, perform ECU Reset on the Auxiliary Electrical Heater Module (AEHM).
3. Cycle the ignition off and back on.
4. With the scan tool, read AEHM DTCs.

Is this DTC active?

Yes

- Replace the Auxiliary Electrical Heater Module (AEHM).
- Perform the BODY VERIFICATION TEST. Verification Tests.

No

- Test Complete.