B1324 - HVAC Systems - Automatic

Diagnostic Trouble Code Chart:

Wiring Schematic:

CIRCUIT DESCRIPTION
The A/C pressure sensor is a located in the high pressure side of the A/C system. The A/C pressure sensor is used by the Powertrain Control Module (PCM) and the HCM to monitor A/C pressure. The Dash Integration Module (DIM) uses this information to command ON the engine cooling fans when the A/C pressure is high and to keep the compressor disengaged when the A/C pressure is excessively high.

The PCM supplies a 5 volt reference and a sensor ground. Changes in the A/C pressure will cause the A/C pressure signal input to the PCM to vary. The PCM monitors the A/C refrigerant pressure circuit and can determine when the signal is out of range of the sensor. When the signal is out of range for a period of time the PCM will set a DTC. The PCM will set DTC B1324. When the A/C pressure is high, above 2969 kPa (430 psi) the A/C compressor clutch will not engage.

CONDITIONS FOR SETTING THE DTC
^ The engine is running.
^ A/C is requested.
^ The A/C pressure is greater than 2969 kPa (430 psi).

ACTION TAKEN WHEN THE DTC SETS
The A/C compressor clutch will not engage.

CONDITIONS FOR CLEARING THE DTC
^ Using a Scan Tool
^ A history DTC will clear after 40 consecutive ignition cycles have occurred without a malfunction.
^ The battery voltage for the HMC is interrupted.
^ A/C pressure drops below 1386 kPa (201 psi).

DIAGNOSTIC AIDS
Check the following conditions:
^ A malfunction within the refrigerant system causing high pressure.
^ Poor connection at the PCM.
^ Damaged harness. Inspect the wiring harness for damage.
^ If the harness appears to be OK, observe the A/C pressure display on the scan tool while moving connectors and wiring harnesses related to the A/C pressure sensor. A change in the A/C pressure display will indicate the location of the malfunction.

TEST DESCRIPTION
The numbers below refer to the step numbers on the diagnostic table.
1. Perform the Body Control Module (BCM) diagnostic system check before continuing with the diagnosis of this DTC.
3. Determines if the Scan Tool pressure reading is accurate.
4. Determines if the sensor is operating.
7. Clears all of the DTCs after the repair procedures are complete.