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 refrigerant pressure. The PCM uses this information to turn ON the engine coolant fans when the A/C refrigerant pressure is high and to disengage the A/C relay when the 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 ground to the sensor. The A/C pressure sensor varies the 5 volt reference relative to changes in the A/C refrigerant pressure. The PCM monitors the A/C refrigerant pressure signal to determine when the the A/C pressure is outside the calibrated range of the sensor. When the signal is out of range (high or low) for a prolonged period of time, the PCM sets DTC P0530. When DTC P0530 sets, the PCM disengages the A/C relay to disable the A/C compressor clutch. This is done to protect the A/C 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.
OR
The A/C 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.
- A/C compressor operation will be disabled while the high or low pressure indication exists.
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 Clear Info function or by disconnecting the PCM battery feed. |
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 A/C 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 A/C pressure display on the scan tool while moving connectors and 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 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
The number(s) below refer to the step number(s) on the Diagnostic Table.
-
NThe normal A/C refrigerant pressure sensor signal voltage is between 0.1 and 4.8 volts. If the A/C voltage is within range, review the Fail Records data to determine the conditions that were present when DTC P0530 set.
-
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 powertrain control module (PCM) is malfunctioning.
-
This vehicle is equipped with a PCM which utilizes an electrically erasable programmable read-only memory (EEPROM). When the PCM is replaced, the new PCM must be programmed.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Did you perform the Powertrain On-Board Diagnostic (OBD) System Check? | -- | ||
Use a scan tool in order to observe the A/C High Side Pressure. Is the A/C High Side Pressure less than the specified value? | 0.3 V | |||
3 | Is the A/C High Side Pressure greater than the specified value? | 4.8 V | Go to Diagnostic Aids | |
Disconnect the A/C refrigerant pressure sensor while using a scan tool in order to observe the A/C High Side Pressure. Is the voltage near the specified value? | 0 V | |||
5 |
Is the A/C High Side Pressure near the specified value? | 5 V | ||
6 | Use a digital multimeter (DMM) in order to measure the voltage between the 5 volt reference B circuit and the ground circuit at the A/C refrigerant pressure sensor harness connector. Is the voltage near the specified value? | 5 V | ||
7 | Inspect for a faulty 5 volt reference B circuit terminal connection at the PCM. Refer to Connector Repairs in Wiring Systems. Was a problem found? | -- | ||
8 | Test for an open or a short to ground in the 5 volt reference B circuit. Refer to Wiring Repairs in Wiring Systems. Was a problem found? | -- | ||
9 | Inspect the A/C refrigerant pressure signal circuit for a faulty terminal connection at the PCM. Refer to Connector Repairs in Wiring Systems. Was a problem found? | -- | ||
10 | Test the A/C refrigerant pressure signal circuit between the sensor connector and the PCM for an open or a short to ground. Refer to Wiring Repairs in Wiring Systems. Was a problem found? | -- | ||
11 | Test the A/C refrigerant pressure signal circuit between the sensor connector and the PCM for a short to voltage. Refer to Wiring Repairs in Wiring Systems. Was a problem found? | -- | ||
12 | Test for a short to voltage on the 5 volt reference B circuit. Refer to Wiring Repairs in Wiring Systems. Was a problem found? | -- | ||
13 | Inspect for a faulty sensor ground circuit terminal connection at the PCM. Refer to Connector Repairs in Wiring Systems. Was a problem found? | -- | ||
14 | Inspect for a faulty sensor ground circuit terminal connection at the A/C refrigerant pressure sensor connector. Refer to Wiring Repairs in Wiring Systems. Was a problem found? | -- | ||
15 | Test for an open in the sensor ground circuit. Refer to Wiring Repairs in Wiring Systems. Was a problem found? | -- | ||
16 | Inspect for a faulty 5 volt reference B circuit or A/C refrigerant pressure signal circuit terminal connection at the sensor. Refer to Connector Repairs in Wiring Systems. Was a problem found? | -- | ||
17 | Replace the malfunctioning harness connector terminal. Refer to Connector Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
18 | Locate and repair an open/short circuit in the wiring harness as necessary. Refer to Wiring Repairs in Wiring Systems. Did you complete the repair? | -- | -- | |
19 | Replace the A/C refrigerant pressure sensor. Refer to A/C Refrigerant Pressure Sensor Replacement in HVAC System - Manual. Did you complete the repair? | -- | -- | |
|
Important:: The replacement PCM must be programmed. Refer to Powertrain Control Module Replacement/Programming Replace the PCM. Did you complete the repair? | -- | -- | ||
21 |
Is the A/C High Side Pressure within the specified range? | 0.1 V-4.8 V | System OK |
