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P0532



DTC P0532

DTC DESCRIPTOR

DTC P0532
Air Conditioning (A/C) Pressure Sensor Circuit Low Voltage

DTC P0533
Air Conditioning (A/C) Pressure Sensor Circuit High Voltage

DIAGNOSTIC FAULT INFORMATION






IMPORTANT: Always perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Testing and Inspection

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 causing the A/C refrigerant pressure sensor signal to the ECM to very. 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 engine is running
- Any of the conditions for setting the DTC are met for 15 seconds

CONDITIONS FOR SETTING THE DTC

P0532
The ECM detects that the A/C pressure is less than 0 psi (0.20 volts).

P0533
The ECM detects that the A/C pressure is more than 428 psi (4.92 volts).

ACTION TAKEN WHEN THE DTC SETS
- The malfunction indicator lamp (MIL) will not illuminate.
- The ECM stores the DTC in 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 ignition cycles have occurred without a malfunction.
- The DTC can be cleared by using the scan tool.

DIAGNOSTIC AIDS
Test the following conditions:
- Visually inspect the sensor for contamination or damage.
- Inspect for the following that may affect the sensors accuracy:
- A malfunction within the refrigerant system causing high pressure.
- Visually inspect the A/C components and lines for damage.

CIRCUIT/SYSTEM VERIFICATION
1. The ambient air temperature must be above 3°C (38°F).
2. The A/C refrigerant within the system must be adequately charged.

CIRCUIT/SYSTEM TESTING
1. With the ignition OFF, inspect the A/C compressor for free rotation. Start the engine; place the HVAC control assembly in the OFF position.
- If the compressor is engaged than refer to HVAC compressor clutch does not disengage. Compressor Clutch Does Not Disengage
2. Install a scan tool, turn ON the ignition, with the engine OFF. Observe the A/C Refrigerant Pressure parameter in the ECM General Info Input/Outputs data list. Expected values would be between 0.2 to 4.9 volts.
- If the observed voltage is between the expected voltages go to Diagnostic Aids. Component Tests and General Diagnostics
- If the reading is out of the specified range, turn the ignition OFF, disconnect the A/C refrigerant pressure sensor. Turn the ignition back ON, with the engine OFF. Observe the A/C Refrigerant Pressure parameter in the ECM General Info Inputs/Outputs data list. Expected value would be less than 0.2 volts.
- If the observed voltage is greater than the expected value than test the signal circuit of the A/C refrigerate pressure sensor for a short to voltage. If the problem is solved clear the DTC and see if the DTC resets.
3. No problem is found than inspect for poor connections at the harness connector of the ECM.
- If a problem is found and repaired clear the DTC and see if the DTC resets.
- If no problem is found than replace the ECM. Clear codes and retest.
- If the observed voltage is less than the expected value than turn the IGN OFF. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the A/C refrigerant pressure sensor and the signal circuit of the A/C refrigerant pressure sensor. Turn the ignition ON, with scan tool observe the A/C Refrigerant Pressure parameter in the ECM General Info Inputs/Outputs data list. Specified value 4.9 volts.
- If the observed voltage is less then the specified value than test the 5-volt reference circuit of the A/C refrigerant pressure sensor for a short to ground, high resistance, of an open. If a problem is found and corrected. Clear codes and retest.
- If no problem is found than test the signal circuit of the A/C refrigerant pressure sensor for a short to ground, high resistance, or an open, if a problem is found and corrected than clear codes and retest.
- If no problem is found than inspect for poor connection at the harness connector of the ECM, if a problem is found and corrected, clear codes and retest.
- If no problem is found, replace the ECM. Clear codes and retest.
- If the observed voltage is greater than the specified value than disconnect the fused jumper wire, measure the voltage between the 5-volt reference circuit of the A/C refrigerant pressure sensor and the low reference circuit of the A/C refrigerant pressure sensor. Specified value 4.9 volts.
- If the observed voltage is greater than the specified voltage than test the 5-volt reference circuit of the A/C refrigerant pressure sensor for a short to voltage. If a problem is found and corrected than clear codes and retest.
- If the observed voltage is less then the specified voltage. Inspect for poor connections at the harness connector of the ECM. If a problem is found and corrected. Clear codes and retest.
- If no problem is found than replace the ECM. Clear codes and retest.
- If the observed voltage is less than the specified voltage than turn OFF the ignition. Disconnect the negative battery cable, measure the resistance from the low reference circuit of the A/C refrigerant pressure sensor and ground. Specified value 5 ohms.
- If the resistance is greater than the specified value than disconnect the ECM. Test the low reference circuit of the A/C refrigerant pressure sensor for a high resistance or an open. If a problem was found and corrected, clear codes and retest.
- If no problem was found, inspect for poor connections at the harness connector of the ECM. If the problem was found and corrected, clear codes and retest.
- If no problem was found replace the ECM. Retest the system.
- If the resistance is less than the specified value than inspect for a poor connections at the harness connector of the A/C refrigerant pressure sensor. If the problem was found and corrected. Clear codes and retest.
- If no problem was found, replace the A/C refrigerant pressure sensor. Clear codes and retest.

REPAIR INSTRUCTIONS

IMPORTANT: Always perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests
- Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement
- Control Module References for ECM replacement, setup, and programming.
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