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For 1990-2009 cars only

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

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

5-Volt Reference Circuit

P0532

P0532

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A/C Refrigerant Pressure Sensor Signal Circuit

P0532

P0532

P0533

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Low Reference Circuit

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P0533

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Circuit/System Description

The powertrain control module (PCM) 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 PCM 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 PCM commands the cooling fans on. When pressure is too high or too low, the PCM 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 volts.

Conditions for Setting the DTC

    • The PCM detects that the A/C pressure is less than 1 psi (0.01 volt).
    • The PCM detects that the A/C pressure is more than 428 psi (4.92 volts).

Action Taken When the DTC Sets

    • The PCM will not illuminate the malfunction indicator lamp (MIL)
    • The PCM 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 PCM 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

HVAC Connector End Views

Description and Operation

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

Electrical Information Reference

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

Scan Tool Reference

    •  Scan Tool Output Controls
    •  Scan Tool Data List
    •  Scan Tool Data Definitions

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the A/C pressure sensor.
  2. Ignition OFF, test for less than 1 ohm between the low reference circuit terminal A and ground.
  3. If greater than specified value, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the PCM.
  4. Ignition ON, test for 4.8-5.2 volts between the 5-volt reference circuit terminal B and ground.
  5. If less than 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 PCM.
    If greater than specified range, test the 5-volt reference circuit for a short to voltage. If the circuit tests normal, replace the PCM.
  6. Ignition OFF, disconnect the C1 harness connector at the PCM.
  7. Ignition ON, test for less than 0 volts on the signal circuit terminal C.
  8. If greater than the specified value, test the signal circuit for an short to voltage.
  9. Test for infinite resistance between the signal circuit terminal C and ground.
  10. If greater than the specified value, test the signal circuit for short to ground.
  11. Test for less that 1 ohm between the signal circuit terminal 11 and the signal circuit terminal C.
  12. If greater than the specified value, test the signal circuit for an open/high resistance. If the circuit tests normal, replace the A/C pressure sensor. If the DTC resets, replace the PCM.

Repair Instructions

    •  Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement
    •  Powertrain Control Module Replacement