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
When the A/C is requested, the Front Controls Interface Module (FCIM) sends the button press message over the Infotainment Controller Area Network (I-CAN) to the Instrument Panel Cluster (IPC) module. The IPC (Instrument Panel Cluster) module then sends the button press message to Body Control Module (BCM) over the High Speed Controller Area Network (HS-CAN). The BCM (Body Control Module) then sends the button press message to the HVAC module over the Medium Speed Controller Area Network (MS-CAN). Lastly the HVAC module sends an A/C request message through the MS-CAN (Medium Speed Controller Area Network) to the BCM (Body Control Module) and the BCM (Body Control Module) sends the A/C request through the HS-CAN (High Speed Controller Area Network) to the PCM.
- DTC P1464 (A/C Demand Out Of Self Test Range)- This DTC sets when the PCM senses an A/C request during a PCM self-test.
This pinpoint test is intended to diagnose the following:
- Wiring, terminals or connectors
- FCIM (Front Controls Interface Module)
- PCM
- HVAC module
PINPOINT TEST N : THE AIR CONDITIONING (A/C) IS ALWAYS ON - A/C MODE ALWAYS COMMANDED ON
N1 CHECK THE AIR CONDITIONING SWITCH STATUS (CC_SW_AC) FCIM (Front Controls Interface Module) PID WITH THE A/C OFF
- Ignition ON.
- Enter the following diagnostic mode on the scan tool: Front Controls Interface Module (FCIM) DataLogger.
- Monitor the CC_SW_AC FCIM (Front Controls Interface Module) PID
- Select PANEL press the A/C button (indicator off) on the HVAC controls.
Does the CC_SW_AC HVAC PID read Inactive?
Yes
GO to N2.
No
INSTALL a new Front Controls Interface Module (FCIM). TEST the system for normal operation.
N2 CHECK THE AIR CONDITIONING REQUEST SIGNAL (AC_REQ) PCM PID WITH THE A/C OFF
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Select PANEL press the A/C button (indicator off) on the HVAC controls.
- Monitor the AC_REQ PCM PID
Does the AC_REQ PCM PID read OFF?
Yes
GO to N5.
No
GO to N3.
N3 CHECK THE AIR CONDITIONING REQUEST SIGNAL (AC_REQ) PCM PID WITH HVAC MODULE DISCONNECTED
- Disconnect: HVAC Module- Electronic Manual Temperature Control (EMTC) C2357.
- Disconnect: HVAC Module- Dual Automatic Temperature Control (DATC) C228A.
- Enter the following diagnostic mode on the scan tool: PCM DataLogger.
- Monitor the AC_REQ PCM PID
Does the AC_REQ PCM PID read OFF?
Yes
GO to N4.
No
GO to N5.
N4 CHECK THE HVAC MODULE CONNECTION
- Inspect the HVAC module component and harness side connectors for:
- corrosion
- damaged pins
- pushed-out terminals
- Connect and correctly seat all the HVAC module connectors.
- Clear the DTCs.
- Enter the following diagnostic mode on the scan tool: Self-Test- HVAC Module.
- 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. TEST the system for normal operation.
N5 CHECK THE PCM CONNECTION
- Disconnect all the PCM connectors.
- Inspect the PCM component and harness side connectors for:
- corrosion
- damaged pins
- pushed-out terminals
- Connect and correctly seat all the PCM connectors.
- Clear the DTCs.
- Enter the following diagnostic mode on the scan tool: Self-Test- PCM.
- 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.