Mode 2 Overcurrent (Single-Zone)

MODE 2 OVERCURRENT (SINGLE-ZONE)

Mode 2 Overcurrent (Single-Zone):

Theory of Operation

NOTE: Diagnose and repair all Actuator Circuit Test faults before diagnosing Overcurrent DTCs.

The A/C Heater Control monitors the door driver circuits during actuator operation for shorts to ground, shorts to battery, and shorts to other door driver circuits. If detected, the A/C Heater Control reports these types of faults as Overcurrent DTCs. It is important to note that Overcurrent DTCs do not indicate where or what type of short is present and that additional system testing is necessary to provide more details about the reported fault.

WHEN MONITORED
When actuator movement is requested.

SET CONDITION
If the A/C Heater Control detects an excessive current draw on any of the door driver circuits while attempting to drive the Mode Door Actuator 2. Note that only one Overcurrent DTC can set per ignition cycle.

POSSIBLE CAUSES
- (C32) Recirculation door driver circuit/(C61) blend door driver circuit/(C801) mode door 1 driver circuit/(C29) mode door 2 driver circuit shorted to ground
- (C32) Recirculation door driver circuit/(C61) blend door driver circuit/(C801) mode door 1 driver circuit/(C29) mode door 2 driver circuit shorted to voltage
- (C32) Recirculation door driver circuit/(C61) blend door driver circuit/(C801) mode door 1 driver circuit/(C29) mode door 2 driver circuit shorted together
- Blend door actuator/mode door actuator 1/mode door actuator 2/recirculation door actuator
- A/C heater control

NOTE: This DTC must be active for the result of this test to be valid. Do not perform this test if this DTC is stored. Refer to HVAC System Test for stored DTC test procedures. HVAC System Test

Diagnostic Test

1. RUN THE ACTUATOR CIRCUIT TEST
Turn the ignition on.
With the DRBIII(R) in HVAC, select System Tests and then select Actuator Circuit Test.
Allow the test to run to completion before proceeding.

Q: Does the DRBIII(R) display any Actuator Circuit Test fault messages?

YES: Diagnose and repair the fault(s). Refer to ACTUATOR CIRCUIT TEST DIAGNOSTICS (SINGLE-ZONE). Heating & A/C System
NO: Go To 2

2. CHECK THE (C32) RECIRCULATION DOOR DRIVER CIRCUIT FOR A SHORT TO THE (C61) BLEND DOOR DRIVER CIRCUIT, THE (C801) MODE DOOR 1 DRIVER CIRCUIT, & THE (C29) MODE DOOR 2 DRIVER CIRCUIT




Turn the ignition off.
Disconnect the A/C Heater Control C1 harness connector.
Measure the resistance between the (C32) Recirculation Door Driver circuit and the (C61) Blend Door Driver circuit, the (C801) Mode Door 1 Driver circuit, and the (C29) Mode Door 2 Driver circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 10k ohms on any of the circuits?

YES: Repair all circuits with a resistance below 10k ohms for a short to the (C32) Recirculation Door Driver circuit. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 3

3. CHECK THE (C61) BLEND DOOR DRIVER CIRCUIT FOR A SHORT TO THE (C801) MODE DOOR 1 DRIVER CIRCUIT & THE (C29) MODE DOOR 2 DRIVER CIRCUIT




Measure the resistance between the (C61) Blend Door Driver circuit and the (C801) Mode Door 1 Driver circuit and the (C29) Mode Door 2 Driver circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 10k ohms on any of the circuits?

YES: Repair all circuits with a resistance below 10k ohms for a short to the (C61) Blend Door Driver circuit. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 4

4. CHECK THE (C801) MODE DOOR 1 DRIVER CIRCUIT FOR A SHORT TO THE (C29) MODE DOOR 2 DRIVER CIRCUIT




Measure the resistance between the (C801) Mode Door 1 Driver circuit and the (C29) Mode Door 2 Driver circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 10k ohms?

YES: Repair the (C29) Mode Door 2 Driver circuit for a short to the (C801) Mode Door 1 Driver circuit. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Go To 5

5. CHECK THE (C34) COMMON DOOR DRIVER CIRCUIT FOR A SHORT TO THE (C32) RECIRCULATION DOOR DRIVER CIRCUIT, THE (C61) BLEND DOOR DRIVER CIRCUIT, THE (C801) MODE DOOR 1 DRIVER CIRCUIT, & THE (C29) MODE DOOR 2 DRIVER CIRCUIT




Measure the resistance between the (C34) Common Door Driver Circuit and the (C32) Recirculation Door Driver circuit, the (C61) Blend Door Driver circuit, the (C801) Mode Door 1 Driver circuit, and the (C29) Mode Door 2 Driver circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 30.0 ohms on any of the circuits?

YES: Go To 6
NO: Go To 7

6. CHECK THE DOOR DRIVER CIRCUITS WHOSE RESISTANCE WAS BELOW 30.0 OHMS IN THE PREVIOUS STEP FOR A SHORT TO THE (C34) COMMON DOOR DRIVER CIRCUIT




Disconnect all door actuator harness connectors whose circuit resistance was below 30.0 ohms.
Measure the resistance between the (C34) Common Door Driver circuit and each applicable door driver circuit in the A/C Heater Control C1 harness connector.

Q: Is the resistance below 10k ohms on any of the circuits?

YES: Repair the door driver circuits with a resistance below 10k ohms for a short to the (C34) Common Door Driver circuit. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test
NO: Replace all door actuators with a resistance below 30.0 ohms. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test

7. RUN THE ACTUATOR CIRCUIT TEST
Reconnect the A/C Heater Control C1 harness connector.
Turn the ignition on.
With the DRBIII(R) in HVAC, select System Tests and then select Actuator Circuit Test.
Allow the test to run to completion before proceeding.

Q: Does the DRBIII(R) display any Actuator Circuit Test fault messages?

YES: Diagnose and repair the fault(s). Refer to ACTUATOR CIRCUIT TEST DIAGNOSTICS (SINGLE-ZONE). Heating & A/C System
NO: Replace the A/C Heater Control. Perform BODY VERIFICATION TEST - VER 1. Body Verification Test