Diagnostic Instructions

DTC Descriptor

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

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

Diagnostic Fault Information

Circuit	Short to Ground	Open/High Resistance	Short to Voltage
5 -Volt Reference Circuit	P0532	P0532	P0533
A/C Refrigerant Pressure Sensor Signal Circuit	P0532	P0533	P0532
Low Reference Circuit	--	P0532	P0533

Circuit/System Description

The engine control module (ECM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The 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 ECM to vary. When the pressure is low, the signal voltage is low. When the 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

Conditions for Setting the DTC

Action Taken When the DTC Sets

Conditions for Clearing the DTC

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

HVAC Connector End Views

Electrical Information Reference

Scan Tool Reference

Circuit/System Verification

Ignition ON, observe the scan tool A/C High Side Pressure parameter in the ECM. The reading should be between 0.1 and 4.90 volts (1 and 425 psi), and change with pressure.

Circuit/System Testing

1. Ignition OFF, disconnect the A/C Refrigerant Pressure 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 and ground.

⇒	If greater than 1.0 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 and ground.

⇒	If less than 4.8 volts, 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 5.2 volts, 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 0.1 volts (1 psi).

⇒	If greater than 0.1 volts (1 psi), test the signal circuit terminal 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 and the 5-volt reference circuit terminal. Verify the scan tool A/C Refrigerant High Side Pressure Sensor is greater than 4.90 volts (425 psi).

⇒	If less than 4.90 volts (425 psi), 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.

Repair Instructions

Important: Always perform Diagnostic Repair Verification after completing the diagnostic procedure.