P0533

DTC P0532 or P0533

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview)provides an overview of each diagnostic category.

DTC Descriptors
DTC P0532
- Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit

DTC P0533
- Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit Low Voltage

Diagnostic Fault Information





Circuit/System Description

The engine control module (ECM) monitors the refrigerant pressure through the A/C refrigerant pressure switch signal circuit. The ECM supplies a 5-volt reference and a low reference to the sensor. Changes in the A/C refrigerant pressure cause the 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.

Conditions for Running the DTC

* The ECM detects that the A/C pressure is less than 1 psi (0.01 volt).
* The ECM detects that the A/C pressure is greater than 428 psi (4.92 volts).

Conditions for Setting the DTCs

* The ECM detects that the A/C pressure is less than 1 psi (0.01 volt).
* The ECM detects that the A/C pressure is greater than 428 psi (4.92 volts).

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

A history DTC clears after 40 consecutive warm-up cycles have occurred without a malfunction.

Reference Information
Schematic Reference

HVAC Schematics (Electrical Diagrams)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Manual HVAC Description and Operation (HVAC - Manual)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning)for scan tool information


Circuit/System Verification

Ignition ON, observe the scan tool A/C High Side Pressure Sensor parameter. The reading should be between 1 psi and 428 psi.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector A/C pressure sensor.
2. Ignition OFF, test for less than 1 ohm between the low reference circuit terminal 1 and ground.

• If greater than 1 ohm, test the low reference circuit 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.

• 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 428 psi.

• If greater than the specified range, 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 428 psi.

• If less than the specified range, test the signal circuit for short to ground or an open/high resistance. If the circuit tests normal, replace the ECM.

6. If all circuits test normal, test or replace the A/C pressure sensor.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (Service and Repair)
* Heater and Air Conditioning Control Replacement (Service and Repair)
* Control Module References (Programming and Relearning)for ECM replacement, setup, and programming