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For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2003 🢒 GMC K Sierra - 4WD 🢒 HVAC 🢒 HVAC Systems - Automatic 🢒 DTC P0530

DTC P0530 LU3, LR4, LM7, LQ4 and L18

Circuit Description

The powertrain control module (PCM) or engine control module (ECM) 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 too high the PCM will not allow the A/C compressor clutch to engage.

Conditions for Running the DTC

The PCM/ECM detects an A/C request.

Conditions for Setting the DTC
    • The A/C refrigerant pressure sensor signal is less than 0.1 volts for 5 seconds.
    • The A/C refrigerant pressure sensor signal is greater than 4.9 volts for 5 seconds.

Action Taken When the DTC Sets

The malfunction indicator lamp (MIL) will not illuminate.

Conditions for Clearing the DTC
    • The DTC will become history if the PCM/ECM no longer detects a failure.
    • The history DTC will clear after 40 fault-free ignition cycles.
    • The DTC can be cleared with a scan tool.

Diagnostic Aids

For an intermittent, 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 low voltage range.

    2.

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

    3.

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

    4.

  4. Tests for a high resistance or an open in the low reference circuit.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

1

Did you perform the HVAC Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Automatic

2
  1. Turn ON the ignition with the engine OFF.
  2. With a scan tool, observe the A/C Pressure Sensor parameter in the Powertrain Engine Data list.

Does the scan tool indicate the A/C Pressure Sensor parameter is within the specified range?

0.1-4.9 V

Go to Diagnostic Aids

Go to Step 3

3

  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 Pressure Sensor parameter.

Does the scan tool indicate that the A/C Pressure Sensor parameter is less than the specified value?

0.09 V

Go to Step 4

Go to Step 10

4

  1. Turn OFF the ignition.
  2. 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.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the A/C Pressure Sensor parameter.

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

4.9 V

Go to Step 8

Go to Step 5

5

  1. Disconnect the fused jumper wire.
  2. Measure the voltage between the 5-volt reference circuit of the A/C refrigerant pressure sensor and the low reference circuit of the A/C refrigerant pressure sensor.

Does the voltage measure less than the specified value?

5.1 V

Go to Step 6

Go to Step 7

6

  1. Turn OFF the ignition.
  2. Disconnect the negative battery cable.
  3. Measure the resistance from the low reference circuit of the A/C refrigerant pressure sensor to a good ground.

Does the resistance measure less than the specified value?

5 ohms

Go to Step 12

Go to Step 11

7

Test the 5-volt reference circuit of the A/C refrigerant pressure sensor for a short to voltage. 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 a short to ground, 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 9

9

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

10

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

11
  1. Disconnect the PCM/ECM.
  2. 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 (PCM) or engine control module (ECM). 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 in Heating Ventilation and Air Conditioning.

Did you complete the replacement?

--

Go to Step 16

Go to Step 15

15

Important: Program the PCM/ECM.

Replace the PCM/ECM. Refer to the appropriate procedure:

    •  Powertrain Control Module Replacement in Engine Controls-4.3L
    •  Powertrain Control Module Replacement in Engine Controls-4.8L, 5.3L, 6.0L
    •  Engine Control Module Replacement in Engine Controls-6.6L
    •  Powertrain Control Module Replacement in Engine Controls-8.1L.

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 2

System OK

DTC P0530 LB7

Circuit Description

The engine control module (ECM) 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 too high the PCM will not allow the A/C compressor clutch to engage.

Conditions for Running the DTC

The ECM detects an A/C request.

Conditions for Setting the DTC
    • The A/C refrigerant pressure sensor signal is less than 0.1 volts for 5 seconds.
    • The A/C refrigerant pressure sensor signal is greater than 4.9 volts for 5 seconds.

Action Taken When the DTC Sets

The malfunction indicator lamp (MIL) will not illuminate.

Conditions for Clearing the DTC
    • The DTC will become history if the ECM no longer detects a failure.
    • The history DTC will clear after 40 fault-free ignition cycles.
    • The DTC can be cleared with a scan tool.

Diagnostic Aids

For an intermittent, refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems.

Test Description

The number below refers to the step number on the diagnostic table.

  1. This step tests the ability of the A/C refrigerant pressure sensor to create a voltage signal for the ECM to monitor the A/C refrigerant pressure. Measure the voltage at the A/C refrigerant pressure sensor, if the voltage is measured at the connector for the sensor, misdiagnosis will occur.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: HVAC Connector End Views

1

Did you perform the HVAC Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - HVAC Systems - Manual

2

Does the scan tool indicate that DTC P0530 is current?

--

Go to Step 3

Go to Diagnostic Aids

3

  1. Turn OFF the ignition.
  2. Disconnect the A/C refrigerant pressure sensor.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the 5 volt reference circuit to the low reference circuit of the A/C refrigerant pressure sensor.

Does the voltage measure near the specified value?

5 V

Go to Step 5

Go to Step 4

4

Measure the voltage from the 5 volt reference circuit of the A/C refrigerant pressure sensor to a good ground.

Does the voltage measure near the specified value?

5 V

Go to Step 7

Go to Step 6

5

  1. With the A/C refrigerant pressure sensor disconnected, connect a jumper wire between the A/C refrigerant pressure sensor and the electrical connector of the A/C refrigerant pressure sensor for the following circuits:
    2. • The 5-volt reference circuit
    • The low reference circuit
  2. Measure the voltage at the A/C refrigerant pressure sensor terminal for the A/C refrigerant pressure sensor signal.

Does the voltage measure less than the specified value?

1.5 V

Go to Step 8

Go to Step 9

6

Test the 5-volt reference circuit of the A/C refrigerant pressure sensor for a short to ground, 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 13

Go to Step 10

7

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 13

Go to Step 10

8

Test the signal circuit of the A/C refrigerant pressure sensor for a short to ground, 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 13

Go to Step 10

9

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 13

Go to Step 11

10

Inspect for poor connections at the harness connector of the ECM. 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 13

Go to Step 12

11

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

Did you complete the replacement?

--

Go to Step 13

--

12

Important: Program the ECM.

Replace the ECM. Refer to Engine Control Module Replacement in Engine Controls-6.6L.

Did you complete the replacement?

--

Go to Step 13

--

13
  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 2

System OK