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Home >> Chevrolet >> 2002 >> Blazer 4D Utility, 4WD, Part Time >> Repair and Diagnosis >> External Pages >> Different car >> Section 995 (HVAC Systems - Automatic) >> Diagnostic Information and Procedures >> DTC P0530 (LU3, LR4, LM7, LQ4 and L18): Air Conditioning (A/C) Refrigerant Pressure Sensor Circuit >> Test Description

Test Description

WARNING: This page is about a different car, the 2004 GMC Sierra, 2004 GMC Cab & Chassis Sierra, 2004 Chevrolet Silverado, and 2004 Chevrolet Cab & Chassis Silverado. However, it is still accessible from the selected car via links, so may be relevant.

The numbers below refer to the step numbers on the diagnostic table.

  1. 3:  Tests for the proper operation of the circuit in the low voltage range.
  2. 4:  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. 5:  Tests for a short to voltage in the 5-volt reference circuit.
  4. 6:  Tests for a high resistance or an open in the low reference circuit.
DTC P0530 (LU3, LR4, LM7, LQ4 and L18)

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 Ω 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: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
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