With Automatic AC

CIRCUIT DESCRIPTION
The powertrain control module (PCM) monitors the high side refrigerant pressure through the A/C refrigerant pressure sensor. The PCM applies 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 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. When the DTC is set, the PCM does not allow the A/C compressor clutch to engage. This is done to protect the compressor.

CONDITIONS FOR RUNNING THE DTC
^ The engine is running.
^ The A/C is requested.

CONDITIONS FOR SETTING THE DTC
^ The A/C refrigerant pressure sensor signal voltage is less than 0.1 volt.
^ The A/C refrigerant pressure sensor signal voltage is more than 4.95 volts.
^ Either of the above conditions are present for more than 20 seconds.

ACTION TAKEN WHEN THE DTC SETS
^ The PCM stores the DTC information into memory when the diagnostic runs and fails.
^ The malfunction indicator lamp (MIL) will not illuminate.
^ The PCM disables the A/C compressor clutch.
^ The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

CONDITIONS FOR CLEARING THE DTC
^ A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction.
^ The current DTC will clear when the diagnostic runs and does not fail.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS

IMPORTANT: Be sure to verify that the PCM engine grounds are secure and clean.

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

If the condition is not present, refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST DESCRIPTION

Steps 1-8:

Steps 9-17:

The numbers below refer to the step numbers on the diagnostic table.
4. Tests for the proper operation of the circuit in the low voltage range.
5. Tests for the proper operation of the circuit in the high voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to ground.
6. Tests for a short to voltage in the 5 volt reference circuit.