Circuit Description
The A/C system uses an A/C refrigerant pressure sensor mounted in the high side of the A/C system to monitor A/C refrigerant pressure. The PCM utilizes this information to turn ON the engine coolant fans when the A/C refrigerant pressure is high.
The A/C refrigerant pressure sensor operates much like other 3-wire sensors. A 5.0 volt reference is supplied to the sensor and returned to the PCM on the signal circuit. As A/C pressure increases or decreases, the resistance of the sensor changes and varies the amount of signal returning to the PCM.
The PCM monitors the A/C refrigerant pressure sensor signal circuit and can determine when A/C pressure is too high or too low. When pressures are out of range (high or low) for a predetermined time, the PCM will disable the A/C compressor clutch and set a DTC P0530. When a DTC P0530 is set, the PCM will disable the A/C compressor clutch so compressor damage does not occur.
Conditions for Setting the DTC
| • | A/C refrigerant pressure sensor indicates A/C refrigerant pressure is below -8.0 psi for 5.0 seconds. |
| • | A/C refrigerant pressure sensor indicates A/C refrigerant pressure is above 448 psi for 5.0 seconds. |
Action Taken When the DTC Sets
| • | The DTC will be stored in the PCM memory when the diagnostic runs and fails. |
| • | The Malfunction Indicator Lamp (MIL) will not illuminate. |
| • | The PCM will record operating conditions at the time the diagnostic fails. This information will be stored in Failure Records. |
Conditions for Clearing the MIL/DTC
| • | A history DTC will clear after 40 consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic. |
| • | A last test failed (Current DTC) will clear when the diagnostic runs and does not fail. |
| • | PCM battery voltage is interrupted. |
| • | Using a scan tool. |
Diagnostic Aids
If the test did not fail this ignition cycle, move related electrical harnesses and connectors while monitoring a scan tool.
For intermittents, refer to Symptoms .
Test Description
Number(s) below refer to step numbers on the diagnostic table.
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Normal A/C voltage is between 1 and 1.8 volts. If A/C voltage is within range, review freeze frame data to determine when DTC P0530 set.
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If A/C pressure/voltage stays high after disconnecting the A/C refrigerant pressure sensor electrical connector, indicates the signal circuit is shorted to a voltage.
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Checks for a good ground circuit.
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Checks the integrity of A/C refrigerant pressure sensor signal circuit.
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If the 5 volt reference circuit has been checked thoroughly (for opens, shorts too ground, PCM connections etc.) and checks OK, then replace the PCM.
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If the ground circuit has been checked thoroughly for opens and PCM connections are OK, then replace the PCM.
Important: Be sure to inspect PCM engine grounds for being secure and clean.
Step | Action | Value(s) | Yes | No |
|---|---|---|---|---|
1 | Was the Powertrain On-Board Diagnostic (OBD) System Check performed? | -- | ||
Does the scan tool indicate A/C High Side between the specified values? | 0.1 V to 1.8 V | |||
3 |
Did the test fail this ignition cycle while operating the vehicle in the conditions that were noted? | -- | Go to Diagnostic Aids | |
4 | Disconnect the A/C refrigerant pressure sensor electrical connector. Does the scan tool indicate the A/C High Side less than the specified value? | 1.0 V | ||
5 | Using a DVM (J 39200), measure voltage from the A/C refrigerant pressure sensor 5.0 volt reference circuit to battery ground. Does the DVM indicate voltage at the specified value? | 5.0 V | ||
6 | Using a DVM (J 39200), measure voltage from the A/C refrigerant pressure sensor 5.0 volt reference circuit to sensor ground circuit. Does the DVM indicate voltage at the specified value? | 5.0 V | ||
7 | Using a jumper wire, jumper 5.0 volt reference circuit to A/C refrigerant pressure sensor signal circuit. Does the scan tool indicate the A/C High Side at the specified value? | 5.0 V | ||
8 | Repair the faulty A/C refrigerant pressure sensor connection or faulty sensor. Is the action complete? | -- | -- | |
9 | Repair the A/C refrigerant pressure sensor signal circuit shorted to voltage. Is the action complete? | -- | -- | |
10 | Repair 5.0 volt reference circuit to A/C refrigerant pressure sensor. Is the action complete? | -- | -- | |
11 | Repair ground circuit to A/C refrigerant pressure sensor. Is the action complete? | -- | -- | |
12 | Repair signal circuit to A/C refrigerant pressure sensor. Is the action complete? | -- | -- | |
13 |
Does the scan tool indicate that this test ran and passed? | -- | ||
14 | Using the scan tool, select Capture Info, Review Info. Are any DTCs displayed that have not been diagnosed? | -- | Go to the applicable DTC table | System OK |
