GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Buick 🢒 2001 🢒 Century 🢒 DTC 🢒 DTC P0530

Circuit Description

The powertrain control module (PCM) monitors the high side refrigerant pressure via a A/C refrigerant pressure sensor. When the pressure is high the signal voltage is high. When the pressure is low the signal voltage is low. When pressure is high the PCM commands the cooling fans on. When pressure is too high or too low the PCM will not allow the A/C compressor clutch to engage. The PCM sends the A/C pressure data to the dash integration module (DIM) over the Class 2 communication line. The DIM will not request A/C compressor clutch engagement if the A/C pressure is too high.

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 volts.

OR

The A/C refrigerant pressure sensor signal voltage is more than 4.9 volts.

Either of the above conditions are present for more than 20 seconds.

Action Taken When the DTC Sets
    • The PCM stores the DTC information into memory when the diagnostic runs and fails.
    • The malfunction indicator lamp (MIL) will not illuminate.
    • The PCM records the operating conditions at the time the diagnostic fails. The PCM stores this information in the Failure Records.

Conditions for Clearing the DTC
    • A History DTC will clear after forty consecutive warm-up cycles, if no failures are reported by this or any other non-emission related diagnostic.
    • The current DTC will clear when the diagnostic runs and does not fail.
    • Use a scan tool in order to clear the diagnostic trouble code.

Diagnostic Aids

If condition not present 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.

  1. Tests for the proper operation of the circuit in the high voltage range.

    2.

  2. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens when you perform this test, the signal circuit is shorted to voltage.

    3.

  3. Tests for a short to ground in the 5-volt reference circuit.

    4.

  4. Tests for a short to voltage, a high resistance, or an open.

    5.

  5. Perform the recalibration procedure for the powertrain control module.

Step

Action

Values

Yes

No

Schematic Reference: HVAC Schematics

1

Did you perform the HVAC Diagnostic Check?

--

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

2

Important: The ambient air temperature must be above 3 degrees Celsius (38 degrees Fahrenheit).

  1. Turn OFF the ignition.
  2. Inspect the A/C compressor for free rotation operation.
  3. Start the engine.
  4. Place the HVAC control module in the OFF position.

Does the A/C compressor operate?

--

Go to HVAC Compressor Clutch Does Not Disengage

Go to Step 3

3
  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the A/C High Side Pressure parameter in the powertrain control module Engine Data 2 list.

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

4

  1. Turn OFF the ignition.
  2. Disconnect the A/C refrigerant pressure sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the A/C High Side Pressure parameter in the powertrain control module Engine Data 2 list.

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 5

Go to Step 9

5

  1. Turn OFF the ignition.
  2. Connect a 3-amp fused jumper wire between the signal circuit of the A/C refrigerant pressure sensor and the low reference circuit of the A/C refrigerant pressure sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the A/C High Side Pressure parameter in the powertrain control module Engine Data 2 list.

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 6

Go to Step 10

6

  1. Turn OFF the ignition
  2. Disconnect the fused jumper wire.
  3. Connect a 3-amp fused jumper wire between the 5-volt reference circuit of the A/C refrigerant pressure sensor and the signal circuit of the A/C refrigerant pressure sensor.
  4. Turn ON the ignition, with the engine OFF.
  5. With a scan tool, observe the A/C High Side Pressure parameter in the powertrain control module Engine Data 2 list.

Does the scan tool indicate that the A/C High Side Pressure parameter is greater than the specified value?

5.1 V

Go to Step 8

Go to Step 7

7

Test the 5-volt reference circuit of the A/C refrigerant pressure sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

8

Test the 5-volt reference circuit of the A/C refrigerant pressure sensor for short to voltage, a 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 16

Go to Step 12

9

Test the signal circuit of the A/C refrigerant pressure sensor for a short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 16

Go to Step 13

10

Test the signal circuit of the A/C refrigerant pressure sensor for a short to voltage, a 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 16

Go to Step 11

11

Test the low reference circuit of the A/C refrigerant pressure sensor for a 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 16

Go to Step 13

12

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 16

Go to Step 14

13

Inspect for poor connections at the harness connector of the powertrain control module. 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 16

Go to Step 15

14

Replace the A/C refrigerant pressure sensor. Refer to Air Conditioning (A/C) Refrigerant Pressure Sensor Replacement Heating, Ventilation and Air Conditioning.

Did you complete the replacement?

--

Go to Step 16

--

15

Important : Perform the programming procedure for the powertrain control module.

Replace the powertrain control module. Refer to Powertrain Control Module Replacement in Engine Controls.

Did you complete the replacement?

--

Go to Step 16

--

16
  1. Use the scan tool in order to clear the DTCs.
  2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

--

Go to Step 3

System OK