HVAC - Automatic
DTC P0532 or P0533
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
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/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 V 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
* Engine is running.
* Any of the conditions for setting the DTC are met for 15 seconds.
* Battery voltage is between 11-18 V.
Conditions for Setting the DTC
* The ECM detects that the A/C pressure is less than 1 psi (0.01 V) sets DTC P0532.
* The ECM detects that the A/C pressure is more than 428 psi (4.92 V) sets DTC P0533.
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 DTC will become history if the ECM no longer detects a failure.
* The history DTC will clear after 40 consecutive fault free ignition cycles have occurred.
Diagnostic Aids
A malfunction within the refrigerant system causing high pressure can cause this DTC to set.
Reference Information
Schematic Reference
HVAC Schematics HVAC - Automatic
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation
* Air Temperature Description and Operation Air Temperature
* Air Delivery Description and Operation Air Delivery
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON
2. Verify DTC P0641 is not set.
• If DTC P0641 is set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
• If DTC P0641 is not set
3. Refer to Circuit/System Testing
Circuit/System Testing
Note: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.
1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the A/C refrigerant pressure sensor. It may take up to 2 minutes for all vehicle systems to power down.
2. Test for less than 5 ohms between the low reference circuit terminal 1 and ground.
• If 5 ohms or greater
1. Ignition OFF, disconnect the X1 harness connector at the HVAC control module.
2. Test for less than 2 ohms in the low reference circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the HVAC control module.
• If less than 5 ohms
3. Disconnect the X1 harness connector at the ECM.
4. Test for infinite resistance between the low reference circuit terminal 13 and ground.
• If less than infinite resistance
Repair the short to ground on the circuit.
• If infinite resistance
5. Ignition ON
6. Test for 4.8-5.2 V between the 5 V reference circuit terminal 2 and ground.
• If less than 4.8 V
1. Ignition OFF, disconnect the X1 harness connector at the HVAC control module.
2. Test for infinite resistance between the 5 V reference circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms on the 5 V reference circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the HVAC control module.
• If greater than 5.2 V
1. Ignition OFF, disconnect the X1 harness connector at the HVAC control module, ignition ON.
2. Test for less than 1 V between the 5 V reference circuit and ground.
• If 1 V or greater, repair the short to voltage on the circuit.
• If less than 1 V, replace the HVAC control module.
• If between 4.8-5.2 V
7. Verify the scan tool A/C High Side Pressure Sensor parameter is less than 0.1 V (1 psi).
• If 0.1 V (1 psi) or greater
1. Ignition OFF, disconnect the X1 harness connector at the HVAC control module, ignition ON.
2. Test for less than 1 V between the signal circuit terminal 3 and ground.
• If greater than 1 V, repair the short to voltage on the circuit.
• If less than 1 V, replace the HVAC control module.
• If less than 0.1 V (1 psi)
8. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the 5 V reference circuit terminal 2.
9. Verify the scan tool A/C High Side Pressure Sensor parameter is greater than 4.9 V (490 psi).
• If 4.9 V (490 psi) or less
1. Ignition OFF, disconnect the X1 harness connector at the HVAC control module.
2. Test for infinite resistance between the signal circuit and ground.
• If less than infinite resistance, repair the short to ground on the circuit.
• If infinite resistance
3. Test for less than 2 ohms on the signal circuit end to end.
• If 2 ohms or greater, repair the open/high resistance in the circuit.
• If less than 2 ohms, replace the HVAC control module.
• If greater than 4.9 V (490 psi)
10. Test or replace the A/C refrigerant pressure sensor.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the repair.
* Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement (Non-HP2) Service and RepairAir Conditioning (A/C) Refrigerant Pressure Sensor Replacement (LGH, LML) Service and Repair
* Control Module References Control Module References for the ECM replacement, programming, and setup