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
| • | Engine is running. |
| • | A/C is requested. |
Conditions for Setting the DTC
| • | A/C refrigerant pressure sensor signal voltage is below 0.1 Volts. |
| • | A/C refrigerant pressure sensor signal voltage is above 4.94 Volts. |
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
Check for the following conditions:
Important: Be sure to inspect PCM engine grounds for being secure and clean.
Important: : Remove any debris from the connector surfaces before servicing a component. Inspect the connector gaskets when diagnosing or replacing a component. Ensure that the gaskets are installed correctly. The gaskets prevent contaminate intrusion.
| • | Poor terminal connection. |
| Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and faulty terminal to wire connection. Use a corresponding mating terminal to test for proper tension. Refer to Intermittents and Poor Connections Diagnosis , and Connector Repairs Wiring Systems. |
| • | Damaged harness. |
| Inspect the wiring harness for damage. If the harness appears to be OK, observe the sensor display on the scan tool while moving connectors and wiring harnesses related to the sensor. A change in the sensor display may indicate the location of the fault. Refer to Wiring Repairs in Wiring Systems. |
| • | Inspect the PCM and the engine grounds for clean and secure connections. |
If the DTC is determined to be intermittent, reviewing the Fail Records can be useful in determining when the DTC was last set.
Test Description
The numbers below refer to the step numbers on the Diagnostic Table:
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Normal A/C pressure sensor signal voltage is between 0.1 and 4.8 volts. If A/C voltage is within range, review Fail Records data to determine the conditions that were present when DTC P0530 set.
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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.
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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 | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain OBD System Check performed? | -- | ||
Note the A/C refrigerant pressure sensor voltage. Is the A/C refrigerant pressure sensor voltage less than the specified value? | 0.1V | |||
3 | Is the A/C refrigerant pressure sensor voltage greater than the specified value? | 4.8V | Go to Diagnostic Aids | |
Disconnect the A/C refrigerant pressure sensor while observing A/C refrigerant pressure sensor voltage on the scan tool. Does the scan tool indicate voltage near the specified value? | 0.0V | |||
5 |
Does the scan tool indicate A/C refrigerant pressure sensor voltage near the specified value? | 5.0V | ||
6 | Using a J 39200 DMM, measure voltage between the 5 Volt Reference B circuit and the ground circuit at the A/C refrigerant pressure sensor harness connector. Is voltage near the specified value? | 5.0V | ||
7 | Test for a poor 5 Volt Reference B circuit terminal connection at the PCM. Refer to Testing for Continuity , Intermittents and Poor Connections Diagnosis , Repairing Connector Terminals , and Connector Repairs . Was a problem found? | -- | ||
8 | Test for an open or a faulty splice in the 5 Volt Reference B circuit. Refer to Wiring Repairs . Was a problem found? | -- | ||
9 | Test the A/C refrigerant pressure signal circuit for a poor terminal connection at the PCM. Refer to Wiring Repairs . Was a problem found? | -- | ||
10 | Test the A/C refrigerant pressure signal circuit between the A/C refrigerant pressure sensor connector and the PCM for an open or short to ground. Refer to Wiring Repairs . Was a problem found? | -- | ||
11 | Test the A/C refrigerant pressure signal circuit between the A/C pressure sensor connector and the PCM for a short to voltage. Refer to Wiring Repairs . Was a problem found? | -- | ||
12 | Test for a short to voltage on the 5 Volt Reference B circuit. Refer to Wiring Repairs . Was a problem found? | -- | ||
13 | Test for a poor sensor ground circuit terminal connection at the PCM. Refer to Testing for Continuity , Intermittents and Poor Connections Diagnosis , Repairing Connector Terminals , and Connector Repairs . Was a problem found? | -- | ||
14 | Test for a poor sensor ground circuit terminal connection at the A/C refrigerant pressure sensor connector. Refer to Testing for Continuity , Intermittents and Poor Connections Diagnosis , Repairing Connector Terminals , and Connector Repairs . Was a problem found? | -- | ||
15 | Test for an open or a faulty splice in the sensor ground circuit. Refer to Wiring Repairs . Was a problem found? | -- | ||
16 | Test for a poor 5 Volt Reference B circuit or A/C refrigerant pressure signal circuit terminal connection at the A/C refrigerant pressure sensor. Refer to Wiring Repairs . Was a problem found? | -- | ||
17 | Replace the faulty harness connector terminal. Refer to Repairing Connector Terminals . Is the action complete? | -- | -- | |
18 | Locate and repair open/short circuit in wiring harness as necessary. Refer to Wiring Repairs . Is the action complete? | -- | -- | |
19 | Replace the A/C refrigerant pressure sensor. Is the action complete? | -- | -- | |
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Important: : The replacement PCM must be programmed. Replace the PCM. Refer to Powertrain Control Module Replacement/Programming . Is the action complete? | -- | -- | ||
21 |
Is the A/C refrigerant pressure sensor voltage between the specified values? | 0.1V - 4.8V | System OK |
