GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2008 🢒 Allure 🢒 Safety and Security 🢒 Supplemental Inflatable Restraints 🢒 DTC P0530, P0532, or P0533

Diagnostic Instructions
    • Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
    • Review Strategy Based Diagnosis for an overview of the diagnostic approach.
    •  Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptor

DTC P0530: Air Conditioning A/C Refrigerant Pressure Sensor Circuit

DTC P0532: Air Conditioning A/C Refrigerant Pressure Sensor Circuit Low Voltage

DTC P0533: Air Conditioning A/C Refrigerant Pressure Sensor Circuit High Voltage

Circuit/System Description

The engine control module (ECM) monitors the high side refrigerant pressure via the A/C refrigerant pressure sensor. The ECM applies 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 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 ECM commands the cooling fans on. When pressure is too high or too low the ECM will not allow the A/C compressor clutch to engage. When the DTC is set, the ECM does not allow the A/C compressor clutch to engage. This is done to protect the compressor.

Conditions for Running the DTC
    • The engine is running.
    • The battery voltage is between 11-18 volts.

Conditions for Setting the DTC

P0530

The A/C refrigerant pressure sensor signal voltage is less than 0.2 volt or more than 4.88 volts for more than 3 seconds.

P0532

The A/C refrigerant pressure sensor signal voltage is less than 0.2 volt for more than 3 seconds.

P0533

The A/C refrigerant pressure sensor signal voltage is more than 4.88 volts for more than 3 seconds.

Action Taken When the DTC Sets
    • The ECM will not illuminate the malfunction indicator lamp (MIL).
    • The ECM stores the failure records.
    • The A/C compressor clutch is disabled.

Conditions for Clearing the DTC
    • The history DTC will clear after 40 consecutive ignition cycles have occurred without a malfunction.
    • The DTC will become history if the ECM no longer detects a failure.

Diagnostic Aids

A malfunction within the refrigerant system causing high pressure can cause this DTC to set.

Reference Information

Schematic Reference

HVAC Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

    •  Air Temperature Description and Operation
    •  Air Delivery Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Ignition ON, observe the scan tool A/C High Side Pressure parameter in the ECM. The reading should be between 0.2 and 4.90 volts (9 and 453 psi), and change with pressure.

Circuit/System Testing
  1. Ignition OFF, disconnect the harness connector at the A/C refrigerant pressure sensor.
  2. Ignition OFF, test for less than 1.0 ohm of resistance between the low reference circuit terminal 1 and ground.
    3. ⇒If greater than the specified range, test the low reference circuit terminal 1 for an open/high resistance. If the circuit tests normal, replace the ECM.
  3. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground.
    4. ⇒If less than the specified range, test the 5-volt reference circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
    ⇒If greater than the specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the ECM.
  4. Verify the scan tool A/C High Side Pressure Sensor parameter is less than 0.2 volts.
    5. ⇒If greater than 0.2 volts, test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the ECM.
  5. Install a 3-amp fused jumper wire between the signal circuit terminal 3 and the 5-volt reference circuit terminal 2. Verify the scan tool A/C High Side Pressure Sensor parameter is greater than 4.90 volts.
    6. ⇒If less than specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.
  6. If all circuits test normal, replace the A/C refrigerant pressure sensor.

Component Testing

Static Test

  1. Ignition OFF, disconnect the harness connector at the A/C refrigerant pressure sensor.
  2. Test for 0.721k ohms of resistance between the 5-volt reference terminal 2 and the low reference terminal 1.
    3. ⇒If the resistance is not equal to or close to the specified value, replace the A/C refrigerant pressure sensor.
  3. Test for 0.721k ohms of resistance between the signal terminal 3 and the low reference terminal 3.
    4. ⇒If the resistance is not equal to or close to the specified value, replace the A/C refrigerant pressure sensor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement
    •  Control Module References for ECM setup, replacement, and programming