Circuit Description
The powertrain control module (PCM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The PCM applies a 5 volt reference and a low reference to the sensor. When the pressure is low, the sensors voltage is low. When the pressure is high, the sensors voltage is high. The PCM sends the A/C pressure data to the body control module over the Class 2 serial data circuit. The body control module will not request A/C clutch engagement if the A/C pressure is too high.
Conditions for Running the DTC
The body control module must be powered.
Conditions for Setting the DTC
The A/C refrigerant pressure is greater than 2968 kPa (430 psi) for more than 500 milliseconds.
Action Taken When the DTC Sets
The body control module disables the A/C clutch.
Conditions for Clearing the DTC
| • | When the A/C refrigerant pressure drops to less than 1386 kPa (201 psi) the body control module will clear the current DTC and go to a history DTC. If A/C is still requested, the body control module will then enable the A/C clutch. |
| • | The history DTC will clear after 50 ignition cycles. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
| • | If DTC B1324 is stored as a history code it indicates that the body control module did receive a high A/C refrigerant pressure message from the PCM. This code could be caused by an intermittent short to voltage on the A/C refrigerant pressure sensor signal circuit which would cause the PCM to set DTC P0530. The code could also be the result of an actual A/C refrigerant over-pressure condition. |
| • | It is possible for the refrigerant system pressure to exceed 2968 kPa (430 psi) during extended engine idle speed with A/C ON and ambient temperatures greater than 41°C (105°F). Other possible causes are: |
| - | An overcharged A/C system |
| - | A failed A/C refrigerant pressure sensor |
| - | Blockage in a refrigerant line |
| - | Debris in front of the A/C condenser |
| - | Radiator or A/C condenser air shields missing or out of location |
| - | Inoperative engine cooling fans |
| - | Extended periods at idle in city traffic followed by rapid acceleration |
| - | Aftermarket products affecting cooling system performance |
| • | If the concern is intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. |
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics Connector End View Reference: HVAC Connector End Views | ||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Is DTC B1324 stored as current? | -- | Go to Step 3 | Go to Diagnostic Aids |
3 |
Does the scan tool indicate system pressure near the gauge pressure within the specified range? | +138 to -138 kPa (+20 to -20 psi) | Go to Air Conditioning (A/C) System Performance Test in Heating, Ventilation and Air Conditioning. | Go to Step 4 |
4 | Replace the A/C refrigerant pressure sensor. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement in Heating, Ventilation and Air Conditioning. Did you complete the replacement? | -- | Go to Step 5 | -- |
5 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
