Pinpoint Test M: The Air Conditioning (A/C) is Inoperative
Climate Control System
Pinpoint Test M: The Air Conditioning (A/C) is Inoperative
Refer to Wiring Diagram Set 54, Manual Climate Control System for schematic and connector information. Diagrams By Number
Refer to Wiring Diagram Set 55, Automatic Climate Control System for schematic and connector information. Diagrams By Number
Normal Operation
Under normal operation, for vehicles equipped with navigation, when 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 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 bus to the HVAC module that MAX A/C has been selected.
For vehicles not equipped with navigation, when A/C is requested, a message is sent from the HVAC module over the MS-CAN bus to the PCM.
Ignition voltage is provided to the A/C clutch relay switch through circuit SBB30 (BN/RD). When the PCM energizes the relay, ignition voltage is supplied to the A/C clutch through circuit CH401 (VT/WH). Ground is supplied for the A/C clutch through circuit GD123 (BK/GY).
This pinpoint test is intended to diagnose the following:
- Fuse(s)
- Wiring, terminals or connectors
- PCM
- HVAC module
- FCIM
- ACM
- A/C evaporator discharge temperature sensor
- A/C pressure transducer
- A/C compressor clutch field coil
- A/C control relay
- A/C clutch air gap
PINPOINT TEST M: THE AIR CONDITIONING (A/C) IS INOPERATIVE
NOTICE: It is important to install relays in their correct position in the Battery Junction Box (BJB). Installing a relay incorrectly may cause wiring shorts or damage to modules. While carrying out diagnostics on relays, have only one BJB relay removed at a time. Failure to follow these instructions may result in damage to the vehicle circuitry or to control modules.
NOTE: Some PCM DTCs may inhibit A/C operation. If any PCM DTCs are retrieved, diagnose those first. Refer to the PCM DTC Chart. PCM DTC Chart
NOTE: Some HVAC DTCs may inhibit A/C operation. If any HVAC DTCs are retrieved, diagnose those first. Refer to the HVAC Module DTC Chart. HVAC Module DTC Chart
NOTE: Before carrying out the following test, check that the A/C system pressure is above 290 kPa (42 psi). If the pressure is below 290 kPa (42 psi), refer to Fluorescent Dye Leak Detection Fluorescent Dye Leak Detection.
M1-M7:
M7-M10:
M10-M11:
