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 Descriptors
DTC P0532: Air Conditioning A/C Refrigerant Pressure Sensor Circuit Low VoltageDTC P0533: Air Conditioning A/C Refrigerant Pressure Sensor Circuit High Voltage
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
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
| • | The engine is running. |
| • | The battery voltage is between 11-18 volts. |
Conditions for Setting the DTC
| • | The ECM detects that the A/C pressure is less than 9 psi (0.02 volt). |
| • | The ECM detects that the A/C pressure is more than 453 psi (4.90 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
| • | The history DTC will clear after 40 consecutive ignition cycles have occurred without a malfunction. |
| • | The DTC or DTCs can be cleared by using the scan tool. |
| • | 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
Connector End View Reference
Electrical Information Reference
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
- Ignition OFF, disconnect the A/C refrigerant pressure harness connector at the A/C refrigerant pressure sensor.
- Ignition OFF, test for less than 10.0 ohms between the low reference circuit terminal 1 and ground.
- Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal 2 and ground.
- Verify the scan tool A/C High Side Pressure Sensor parameter is less than 0.2 volt (9 psi).
- Install a 3A fused jumper wire between the signal circuit terminal 3 and the 5-volt reference circuit terminal 2. Verify the scan tool A/C Refrigerant High Side Pressure Sensor is greater than 4.90 volts (453 psi).
- If all circuits test normal, replace the A/C refrigerant pressure sensor.
| ⇒ | If greater than 1.0 ohm, test the low reference circuit terminal 1 for an open/high resistance. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than 4.8 volts, test the 5-volt reference circuit terminal 2 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 terminal 2 or a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If greater than 0.2 volt (9 psi), test the signal circuit terminal 3 for a short to voltage. If the circuit tests normal, replace the ECM. |
| ⇒ | If less than 4.90 volts (453 psi), test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the ECM. |
Component Testing
Static Test
- Ignition OFF, disconnect the A/C refrigerant pressure sensor harness connector at the A/C refrigerant pressure sensor.
- Test for 0.721k ohms between the 5-volt reference and the low reference terminal.
- Test for 0.721k ohms between the signal terminal and the low reference terminal.
| ⇒ | If the resistance is not equal to or close to the specified value, replace the A/C refrigerant pressure sensor. |
| ⇒ | If the resistance is not equal to or close to the specified value, replace the A/C refrigerant pressure sensor. |
Repair Instructions
Perform Diagnostic Repair Verification after completing the diagnostic procedure.
| • | Control Module References for the ECM setup, replacement, and programming |
