Circuit Description
The A/C system uses an A/C refrigerant pressure sensor mounted in the high pressure side of the A/C refrigerant system to monitor A/C refrigerant pressure. The PCM uses this information to turn ON the engine coolant fans when the A/C refrigerant pressure is high and to keep the compressor disengaged when A/C refrigerant pressure is excessively high or low. The A/C 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 A/C refrigerant pressure will cause the A/C refrigerant pressure input to the PCM to vary. The PCM monitors the A/C 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 A/C compressor clutch to engage. This is done to protect the compressor.
Conditions for Running the DTC
| • | The engine is running. |
| • | A/C is requested. |
Conditions for Setting the DTC
| • | The A/C refrigerant pressure sensor signal voltage is less than 0.1 volt (9 psi). |
| OR |
| • | The A/C refrigerant pressure sensor signal voltage is more than 4.9 volts (472 psi). |
| • | Either of the above conditions are present for more than 20 seconds. |
Action Taken When the DTC Sets
| • | The malfunction indicator lamp (MIL) will not illuminate. |
| • | The PCM will store conditions which were present when the DTC set as Failure Records data only. This information will not be stored as Freeze Frame data. |
Conditions for Clearing the DTC
| • | A history DTC will clear after 40 consecutive warm-up cycles have occurred without a malfunction. |
| • | The DTC can be cleared by using a scan tool. |
Diagnostic Aids
Important: Be sure to inspect PCM engine grounds for being secure and clean.
If DTC P0530 cannot be duplicated, reviewing the Failure Records vehicle mileage since the diagnostic test last failed may help determined how often the condition that caused the DTC to set occurs. This may assist in diagnosing the condition.
If the problem is intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.
Test Description
The numbers below refer to the step numbers on the diagnostic table:
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If the A/C refrigerant pressure signal voltage stays high after disconnecting the A/C refrigerant pressure sensor electrical connector, the signal circuit is shorted to voltage or the PCM is faulty.
-
Tests for a high resistance or an open in the ground circuit.
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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.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
Schematic Reference: HVAC Schematics | ||||
1 | Did you perform the HVAC Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Important: The ambient air temperature must be above 3°C (38°F).
Does the A/C compressor operate? | -- | Go to Step 3 | |
3 |
Does the scan tool indicate that the A/C High Side Pressure parameter is within the specified range? | 0.1-4.9 V | Go to Diagnostic Aids | Go to Step 4 |
Does the scan tool indicate that the A/C High Side Pressure parameter is less than the specified value? | 0.1 V | Go to Step 5 | Go to Step 11 | |
5 |
Does the scan tool indicate that the A/C High Side Pressure parameter is greater than the specified value? | 4.9 V | Go to Step 6 | Go to Step 9 |
6 |
Does the voltage measure less than the specified value? | 5.0 V | Go to Step 7 | Go to Step 8 |
Does the resistance measure less than the specified value? | 5 ohms | Go to Step 13 | Go to Step 12 | |
8 | Test the 5 Volt Reference circuit of the A/C refrigerant pressure sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 |
9 | Test the 5-volt reference circuit of the A/C refrigerant pressure sensor for a short to ground, high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 10 |
10 | Test the A/C refrigerant pressure sensor signal circuit of the A/C refrigerant pressure sensor for a short to ground, high resistance, or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 |
11 | Test the A/C refrigerant sensor signal circuit of the A /C refrigerant pressure sensor for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 |
12 |
Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 14 |
13 | Inspect for poor connections at the harness connector of the A/C refrigerant pressure sensor Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 15 |
14 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 17 | Go to Step 16 |
15 | Replace the A/C refrigerant pressure sensor. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement . Did you complete the replacement? | -- | Go to Step 17 | -- |
|
Important: : Perform the set up procedure for the PCM. Replace the PCM. Refer to Powertrain Control Module Replacement in Engine Controls - 3.4 L. Did you complete the replacement? | -- | Go to Step 17 | -- | |
17 |
Does the DTC reset? | -- | Go to Step 3 | System OK |
