Diagnostic Routine O

Diagnostic Routine O

Diagnostic Overview

The Air Conditioning (AC) Is Always On - AC Mode Always Commanded On

Refer to Wiring Diagram Set 55 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

REFER to Controls and Compressor Cycling.

DTC Fault Trigger Conditions






Pinpoint Test

1. CHECK THE AIR CONDITIONING SWITCH STATUS (CC_SW_AC) PID (Parameter Identification)

1. Using a scan tool, view HVAC (Heating, Ventilation, and Air Conditioning) module PIDs (Parameter Identifications).

2. Monitor the HVAC (Heating, Ventilation, and Air Conditioning) module PID (Parameter Identification) CC_SW_AC.

Does the PID (Parameter Identification) read off?






2. CHECK THE AIR CONDITIONING REQUEST SIGNAL (AC_REQ) PID (Parameter Identification) WITH THE A/C (Air Conditioning) OFF

1. Using a scan tool, view PCM (Powertrain Control Module) PIDs (Parameter Identifications).

2. Monitor the PCM (Powertrain Control Module) PID (Parameter Identification) AC_REQ.

3. Select MAX A/C (Air Conditioning) on the HVAC module.

Does the PID (Parameter Identification) read OFF?






3. CHECK THE AIR CONDITIONING REQUEST SIGNAL (AC_REQ) PID (Parameter Identification) WITH THE A/C (Air Conditioning) OFF

1. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228A.

2. Using a scan tool, view PCM (Powertrain Control Module) PIDs (Parameter Identifications).

3. Monitor the PCM (Powertrain Control Module) PID (Parameter Identification) AC_REQ.

Does the PID (Parameter Identification) read OFF?






4. CHECK FOR CORRECT HVAC (Heating, Ventilation, and Air Conditioning) MODULE OPERATION

1. Ignition OFF.

2. Disconnect and inspect all the HVAC (Heating, Ventilation, and Air Conditioning) module connectors.

3. Repair:

- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary

4. Reconnect the HVAC (Heating, Ventilation, and Air Conditioning) module connectors. Make sure they seat and latch correctly.

5. Operate the system and determine if the concern is still present.

Is the concern still present?






5. CHECK FOR CORRECT PCM (Powertrain Control Module) OPERATION

1. Ignition OFF.

2. Disconnect and inspect all the PCM (Powertrain Control Module) connectors.

3. Repair:

- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary

4. Reconnect the PCM (Powertrain Control Module) connectors. Make sure they seat and latch correctly.

5. Operate the system and determine if the concern is still present.

Is the concern still present?