HVAC System - Manual

DTC P0532 or P0533

Circuit Description

The powertrain control module (PCM) or engine control module (ECM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The PCM or ECM supplies a 5-volt reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the A/C refrigerant pressure sensor signal to the PCM or ECM to vary. When the pressure is high, the signal voltage is high. When the pressure is low, the signal voltage is low. When pressure is high, the PCM or ECM commands the cooling fans on. When pressure is too high or too low, the PCM or ECM will not allow the A/C compressor clutch to engage.

DTC Descriptors

This diagnostic procedure supports the following DTCs:

* DTC P0532 Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit Low Voltage
* DTC P0533 Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit High Voltage

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

All of the following conditions exist for 15 seconds:

* The PCM or ECM detects that the A/C pressure is 9 psi or less (0.20 volt).
* The PCM or ECM detects that the A/C pressure is more than 453 psi (4.92 volts).
* The PCM or ECM detects a too low or too high signal on the A/C refrigerant pressure sensor signal circuit.

Action Taken When the DTC Sets

* The control module stores the DTC information into memory when the diagnostic runs and fails.
* The malfunction indicator lamp (MIL) will not illuminate.
* The A/C compressor clutch is disabled.
* The control module records the operating conditions at the time the diagnostic fails. The control module stores the information in the Failure Records.
* The driver information center (DIC), if equipped, may display a message.

Conditions for Clearing the DTC

* The history DTC will clear after 40 consecutive ignition cycles have occurred without a malfunction.
* The DTC can be cleared by using the scan tool.
* The DTC will become history if the PCM or ECM no longer detects a failure.

Diagnostic Aids

Test the following conditions:

* Visually inspect the sensor for contamination or damage.
* Inspect for the following that may affect the sensors accuracy:

- A malfunction within the refrigerant system causing high pressure
- Visually inspect the A/C components and lines for damage.

* Refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics

Test Description

Step 1 - Step 7:

Step 8 - Step 17:

The numbers below refer to the step numbers on the diagnostic table.
4. This step tests for the proper operation of the circuit in the low voltage range.
5. This step tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
6. This step tests for a short to voltage in the 5-volt reference circuit.
7. This step tests for a high resistance or an open in the low reference circuit.