Pinpoint Test N: The Air Conditioning (A/C) is Always On - A/C Mode Always Commanded ON

Climate Control System

Pinpoint Test N: The Air Conditioning (A/C) is Always On - A/C Mode Always Commanded ON

Normal Operation

Under normal operation, for vehicles equipped with navigation, when the A/C button is pressed, a message is sent from the Front Controls Interface Module (FCIM) over the Medium Speed Controller Area Network (MS-CAN) bus to the HVAC module. The HVAC module then sends an A/C request message over the MS-CAN (Medium Speed Controller Area Network) bus to the Instrument Cluster (IC), then from the IC (Instrument Cluster) through the High Speed Controller Area Network (HS-CAN) bus to the PCM. When MAX A/C is selected on the touch screen, the Audio Control Module (ACM) sends a message over the MS-CAN (Medium Speed Controller Area Network) bus to the HVAC module that MAX A/C has been selected.

For vehicles not equipped with navigation, when A/C is requested, the HVAC module sends an A/C request message over the MS-CAN (Medium Speed Controller Area Network) bus to the IC (Instrument Cluster), then from the IC (Instrument Cluster) through the HS-CAN (High Speed Controller Area Network) bus to the PCM.

This pinpoint test is intended to diagnose the following:

- Wiring, terminals or connectors

- PCM

- HVAC module

PINPOINT TEST N : THE AIR CONDITIONING (A/C) IS ALWAYS ON - A/C MODE ALWAYS COMMANDED ON

NOTE: Before carrying out the following test, diagnose any HVAC, PCM or IC (Instrument Cluster) DTCs.

N1 CHECK THE ACCS PCM PID WITH THE A/C OFF

- Ignition ON.

- Enter the following diagnostic mode on the scan tool: ACCS PCM PID.

- Select PANEL press the A/C button (indicator off) on the HVAC module.

Does the ACCS PCM PID read ON?

Yes
If the vehicle is equipped with navigation, GO to N3.

If the vehicle is not equipped with navigation, GO to N2.

No
GO to N6.

N2 CHECK THE (A/C) SWITCH (CC_SW_AC) HVAC PID WITH THE A/C OFF

- Enter the following diagnostic mode on the scan tool: CC_SW_AC HVAC PID.

- Select PANEL press the A/C button (indicator off) on the HVAC module.

Does the CC_SW_AC HVAC PID read Inactive?

Yes
GO to N6.

No
GO to N5.

N3 CHECK THE A/C INDICATOR WITH THE A/C OFF

NOTE: Before carrying out this test step, be sure all other FCIM (Front Controls Interface Module) button functions are operational. If all other buttons operate correctly, continue with this test step. If multiple buttons are inoperative and DTC U0010:88 is not present, install a new FCIM (Front Controls Interface Module). Test the system for normal operation. If DTC U0010:88 is present, diagnose the DTC first.

- Select PANEL press the A/C button (indicator off) on the HVAC module.

Does the A/C indicator turn off when the A/C button is pressed?

Yes
GO to N5.

No
GO to N4.

N4 CHECK THE MAX A/C OPERATION

NOTE: Before carrying out this test step, be sure all other ACM (Audio Control Module) touch screen functions are operational. If all other touch screen functions operate correctly, continue with this test step. If multiple touch screen functions are inoperative and DTC U0010:88 is not present, install a new ACM (Audio Control Module). Test the system for normal operation. If DTC U0010:88 is present, diagnose the DTC first.

- Select MAX A/C on the navigation screen.

Does the A/C turn off when MAX A/C is selected?

Yes
INSTALL a new FCIM (Front Controls Interface Module). TEST the system for normal operation.

No
GO to N5.

N5 CHECK THE HVAC MODULE CONNECTION

- Inspect the module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.


- Connect and correctly seat all the HVAC module connectors.

- Clear the DTCs.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new HVAC module. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector. CLEAR the DTCs. REPEAT the self-test. TEST the system for normal operation.

N6 CHECK THE PCM CONNECTION

- Disconnect all the PCM connectors.

- Inspect the module connectors for:
- corrosion.
- pushed-out terminals.
- damaged terminals.


- Connect and correctly seat all the PCM connectors.

- Clear the DTCs.

- Operate the system and verify the concern is still present.

Is the concern still present?

Yes
INSTALL a new PCM. TEST the system for normal operation.

No
The system is operating correctly at this time. The concern may have been caused by a loose or corroded connector.