Circuit Description
The air conditioning (A/C) system uses an A/C refrigerant pressure sensor mounted in the high pressure side of the A/C refrigerant system to monitor the A/C refrigerant pressure. The powertrain control module (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 the 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 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. |
| • | The A/C is requested. |
Conditions for Setting the DTC
| • | The A/C refrigerant pressure sensor signal voltage is less than 0.1 volt (34 psi). |
| OR: |
| • | The A/C refrigerant pressure sensor signal voltage is more than 4.9 volts (440 psi). |
| • | Either of the above conditions is present for more than 20 seconds. |
Action Taken When the DTC Sets
The PCM stores conditions which were present when the DTC set as Failure Records only. This information will not be stored as Freeze Frame Records.
Conditions for Clearing the MIL/DTC
| • | The DTC becomes history when the conditions for setting the DTC are no longer present. |
| • | The history DTC clears after 40 malfunction free warm-up cycles. |
| • | The PCM receives a clear code command from the scan tool. |
Diagnostic Aids
Inspect for the following conditions:
Important: Be sure to inspect the PCM engine grounds for being secure and clean.
| • | Poor connection at the PCM and the A/C refrigerant pressure sensor. Inspect harness connectors for the following conditions: |
| - | Backed-out terminals |
| - | Improper mating |
| - | Broken locks |
| - | Improperly formed or damaged terminals |
| - | Poor terminal-to-wire connections |
| • | Use a corresponding mating terminal to test for the proper terminal tension. |
| • | A damaged harness. Inspect the wiring harness for damage. If the harness appears to be OK, observe the A/C pressure display on the scan tool while moving the connectors and the wiring harnesses related to the A/C refrigerant pressure sensor. A change in the A/C pressure display will indicate the location of the malfunction. |
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 be set occurs. This may assist in diagnosing the condition.
Test Description
The numbers below refer to the step numbers on the diagnostic table.
-
If the A/C refrigerant pressure signal voltage remains high after disconnecting the A/C refrigerant pressure sensor, the signal circuit is shorted to voltage or the PCM is faulty.
-
This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read-only memory (EPROM). If the PCM is replaced, the new PCM must be programmed.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board (OBD) Diagnostic System Check? | -- | Go to Step 2 | |
2 |
Is the A/C pressure sensor voltage within the specified range? | 0.1 V -4.9 V | Go to Diagnostic Aids | Go to Step 3 |
Is the A/C pressure sensor voltage less than the specified value? | 0.1 V | Go to Step 4 | Go to Step 9 | |
4 |
Is the A/C pressure sensor voltage more than the specified value? | 4.9 V | Go to Step 5 | Go to Step 7 |
5 |
Is the voltage more than the specified value? | 4.9 V | Go to Step 6 | Go to Step 10 |
6 | Test the 5 volt reference B circuit of the A/C pressure sensor for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
7 | Test the 5 volt reference B circuit of the A/C pressure sensor for a short to ground, high resistance, or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 8 |
8 | Test the signal circuit of the A/C pressure sensor for a short to ground, high resistance, or an open. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
9 | Test the signal circuit of the A /C pressure sensor for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 12 |
10 |
Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 11 |
11 | Inspect for poor connections at the harness connector of the A/C pressure sensor. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 13 |
12 | Inspect for poor connections at the harness connector of the PCM. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems. Did you find and correct the condition? | -- | Go to Step 15 | Go to Step 14 |
13 | Replace the A/C pressure sensor. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement in HVAC. Did you complete the replacement? | -- | Go to Step 15 | -- |
|
Important: The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Did you complete the replacement? | -- | Go to Step 15 | -- | |
15 |
Does the DTC reset? | -- | Go to Step 2 | System OK |
