P0530

Circuit Description

The AC system uses an AC refrigerant pressure sensor mounted in the high pressure side of the AC refrigerant system to monitor AC refrigerant pressure. The PCM uses this information to turn ON the engine coolant fans when the AC refrigerant pressure is high and to keep the compressor disengaged when AC refrigerant pressure is excessively high or low. The AC refrigerant pressure sensor operates like other 3-wire sensors. The PCM applies a 5.0 volt reference and a sensor ground to the sensor. Changes in the AC refrigerant pressure will cause the AC refrigerant pressure input to the PCM to vary. The PCM monitors the AC refrigerant pressure signal circuit and can determine when the signal is outside of the possible range of the sensor. When the signal is out of range (high or low) for a prolonged period of time, the PCM will set DTC P0530. When DTC P0530 is set, the PCM will not allow the AC compressor clutch to engage. This is done to protect the compressor.

Conditions for Running the DTC

^ The engine is running.

^ AC is requested.

Conditions for Setting the DTC

The AC refrigerant pressure sensor signal voltage is less than 0.1 volt.

OR

The AC refrigerant pressure sensor signal voltage is greater than 4.9 volts.

Either of the above conditions for longer than 20 seconds.

Action Taken When the DTC Sets

^ The PCM will not illuminate the Malfunction Indicator Lamp (MIL).

^ The PCM will store conditions which were present when the DTC set as Fail Records data only. This information will not be stored as Freeze Frame data.

Conditions for Clearing the MIL/DTC

^ A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.

^ DTC can be cleared by using the scan tool.

Diagnostic Aids

Check for the following conditions:

Important: Be sure to inspect PCM engine grounds for being secure and clean.

^ Poor connection at PCM and AC Refrigerant Sensor.

Inspect harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, poor terminal to wire connections.

^ Damaged harness.

Inspect the wiring harness for damage. If the harness appears to be OK, observe the AC pressure display on the scan tool while moving connectors and wiring harnesses related to the AC refrigerant pressure sensor. A change in the AC pressure display will indicate the location of the malfunction.

If DTC P0530 cannot be duplicated, reviewing the Fail Records vehicle mileage since the diagnostic test last failed may help determine how often the condition that caused the DTC to be set occurs. This may assist in diagnosing the condition.

Test Description

Number(s) below refer to the step number(s) on the Diagnostic Table.

2. Normal AC refrigerant pressure sensor signal voltage is between 0.1 and 4.8 volts. If AC voltage is within range. review Fail Records data to determine the conditions that were present when DTC P0530 set.

4. If the AC refrigerant pressure signal voltage stays high after disconnecting the AC refrigerant pressure sensor electrical connector, the signal circuit is shorted to voltage or the PCM is malfunctioning.

20. This vehicle is equipped with a PCM which utilizes an Electrically Erasable Programmable Read Only Memory (EEPROM). When the PCM is being replaced, the new PCM must be programmed.