HVAC System - Automatic

DTC P0532 or P0533

Circuit Description

The powertrain control module (PCM) or engine control module (ECM) monitors the high side refrigerant pressure via an A/C refrigerant pressure sensor. The PCM/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/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/ECM commands the cooling fans ON. When pressure is too high or too low, the PCM/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 engine is running.
* A/C has been requested.

Conditions for Setting the DTC

* The PCM/ECM detects the signal circuit is less than 5 counts (0.09 volt) or more than 250 counts (4.9 volts).
* The condition exists for 20 seconds.

Action Taken When the DTC Sets

* The PCM/ECM will not illuminate the malfunction indicator lamp (MIL).
* The PCM/ECM stores the Failure Records.
* The A/C compressor clutch is disabled.

Conditions for Clearing the DTC

* The DTC will become history if the PCM/ECM no longer detects a failure.
* The history DTC will clear after 40 fault-free ignition cycles.
* The DTC can be cleared with a scan tool.

Diagnostic Aids

If the condition is not present, refer to Testing for Intermittent Conditions and Poor Connections in Diagnostic Aids. Component Tests and General Diagnostics

Test Description

Step 1 - Step 9:

Step 10 - Step 17:

The numbers below refer to the step numbers on the diagnostic table.
4. If the pressure signal voltage stays high after disconnecting the pressure sensor electrical connector, the signal circuit is shorted to voltage, or the PCM/ECM is faulty.
7. This step tests for a high resistance or for an open in the ground circuit.
16. This vehicle is equipped with a PCM/ECM which utilizes an electrically erasable programmable read-only memory (EEPROM). Before you replace the PCM/ECM, program the new PCM/ECM.