Powertrain Control Module Controlled Air Conditioning (A/C) Circuit Diagnosis. Oldsmobile Intrigue 2000

For 1990-2009 cars only

Makes 🢒 Oldsmobile 🢒 2000 🢒 Intrigue 🢒 Engine 🢒 Engine Controls - 3.5L 🢒 Powertrain Control Module Controlled Air Conditioning (A/C) Circuit Diagnosis

Refer to

Heater- A/C Control and A/C Compressor Clutch Coil

Low Blower, Cruise and HVAC Fuses
Fuse Block: Heated Mirrors, Crank Signal/BCM/Cluster and IGN 0/Cluster/PCM/BCMFuses
Turn Signal/Corn Lps, Air Bag, Cluster
Turn Signal/Corn Lps, Air Bag, Cluster
Turn Signal/Corn Lps, Air Bag, Cluster
Rear Cmpt Rel, ECM, GEN, Fog Lamps, Fuel Pump, A/C Clutch and Horn FusEs
Ground G113
Ground G113
Ground G113
Rear Cmpt Rel, ECM, GEN, Fog Lamps, Fuel Pump, A/C Clutch and Horn FusEs
Ground G117
Ground G117
Handling ESD Sensitive Parts Notice
Engine Controls Component Views
Powertrain Control Module Description
Transaxle Range Switch Outputs
Cruise Control Module, EBCM and VSS
OBD II Symbol Description Notice
in Engine Controls Schematics.

Circuit Description

When an A/C mode is selected, the A/C control head or the A/C programmer supplies a 12 volt signal to the powertrain control module (PCM) A/C request input. The A/C compressor clutch relay is controlled by the PCM. The PCM provides a ground path for the A/C relay coil. When the A/C compressor relay is engaged, battery voltage is supplied to the compressor clutch coil. The PCM will enable the A/C compressor clutch whenever the engine is running and the A/C has been requested unless one or more of the following conditions are present:

•	The throttle angle is more than 96 percent.

•	The A/C head pressure is more than 440 psi (4.6 volts) or less than 35 psi (0.4 volt) as determined by the A/C refrigerant pressure sensor.

•	The ignition 1 voltage is less than 10.5 volts.

•	The engine speed is more than 4300 RPM for more than 1 second.

•	The engine speed is more than 5400 RPM for any amount of time.

•	The engine coolant temperature (ECT) is more than 124°C (255°F).

•	The intake air temperature (IAT) is less than 5°C (41°F).

Any of the conditions described above will inhibit the A/C compressor relay operation.

Diagnostic Aids

Check for the following conditions:

•	Any poor connection at the PCM -- Inspect the harness connectors for backed out terminals, improper mating, broken locks, improperly formed or damaged terminals, and poor terminal to wire connections.

•

A damaged harness -- Inspect the wiring harness for damage. If the harness appears to be OK, disconnect the PCM, turn the ignition ON, and observe a voltmeter connected to the A/C relay control circuit at the PCM harness connector while moving the connectors and wiring harnesses related to the A/C relay. A change in voltage will indicate the location of the malfunction.

Check for conditions that will disable the A/C operation:

•	The throttle angle is more than 96 percent.

•	The A/C head pressure is more than 440 psi (4.6 volts) or less than 35 psi (0.4 volt) as determined by the A/C refrigerant pressure sensor.

•	The ignition 1 voltage is less than 10.5 volts.

•	The engine speed is more than 4300 RPM for more than 1 second.

•	The engine speed is more than 5400 RPM for any amount of time.

•	The ECT is more than 124°C (255°F).

•	The IAT is less than 5°C (41°F).

Test Description

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

The DTC P1641 diagnostic handles the control portion of the relay circuit. The DTC P0530 diagnostic pertains to the A/C refrigerant pressure sensor. If either DTC is set, perform that diagnostic first.

Under certain conditions, the PCM may engage the A/C compressor clutch briefly at start-up. Answer Yes to this step if the A/C compressor clutch remains engaged after the engine is started with all of the A/C controls in the Off position.

If the refrigerant pressure is low, refer to Heating, Ventilation, and Air Conditioning for the diagnostic procedures.

Check for poor connections and terminal tension at the fuse. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems .

Step

Action

Value(s)

Yes

Did you perform the Powertrain On-Board Diagnostic (OBD) System Check?

Go to Step 2

Go to Powertrain On Board Diagnostic (OBD) System Check

Is DTC P0530 or DTC P1641 set?

Go to the applicable DTC tables

Go to Step 3

Important: The following conditions must be met before continuing with this step:

•	The ambient air temperature must be more than 5°C (41°F).

•	The A/C pressure must be more than 35 psi (0.4 volt).

•	The coolant temperature must be less than 121°C (250°F).

If the refrigerant pressure is low, refer to Cooling Insufficient - Air Conditioning (A/C) System in Heating, Ventilation and Air Conditioning.

Turn the A/C off.
Start the engine.

Is the A/C clutch engaged?

Go to Step 15

Go to Step 4

Select an A/C mode on the HVAC control head.

Is the A/C clutch engaged?

Go to Diagnostic Aids

Go to Step 5

Does the scan tool indicate the A/C Request is Yes?

Go to Step 6

Go to Air Conditioning (A/C) Request Circuit Diagnosis

Turn the engine off. Turn the ignition on.
Check the fuse that supplies power to the relay.

Is the fuse OK?

Go to Step 11

Go to Step 7

Disconnect the control relay for the A/C compressor clutch .
Connect a digital multimeter (DMM) to battery ground and probe the power feed circuits at the relay connector.

Is the resistance more than the specified value?

2 ohms

Go to Step 8

Go to Step 17

Disconnect the compressor clutch connector.
Connect the DMM to battery ground and probe the compressor clutch feed circuit at the relay connector.

Is the resistance more than the specified value?

2 ohms

Go to Step 9

Go to Step 18

Replace the fuse.
Reconnect the relay.
Make sure the vehicle conditions still meet the criteria specified in Step 3.
Start the engine.
Select an A/C mode on the HVAC control head.
Recheck the fuse.

Is the fuse OK?

Go to Step 10

Go to Step 24

Turn the ignition off.
Reconnect the A/C compressor clutch.
Make sure the vehicle conditions still meet the criteria specified in Step 3.
Start the engine.
Select an A/C mode on the HVAC control head.
Recheck the fuse.

Is the fuse OK?

Go to Diagnostic Aids

Go to Step 26

Disconnect the control relay for the A/C compressor clutch .
Probe the power feed circuits in the relay connector with a test lamp connected to ground.

Does the test lamp illuminate?

Go to Step 12

Go to Step 19

Connect the power feed circuit to the compressor clutch feed circuit in the relay connector using a 10 amp fused jumper.

Does the A/C compressor clutch engage?

Go to Step 23

Go to Step 13

Leave the fused jumper in place.
Disconnect the A/C compressor clutch.
Connect the test lamp between the feed circuit and the ground circuit in the compressor clutch harness connector.

Does the test lamp illuminate?

Go to Step 25

Go to Step 14

Move the ground clip of the test lamp to a known good ground.
Probe the feed circuit in the harness connector of the A/C compressor clutch .

Does the test lamp illuminate?

Go to Step 21

Go to Step 20

Disconnect the control relay of the A/C compressor clutch .

Is the A/C compressor still engaged?

Go to Step 16

Go to Step 24

Using the test lamp connected to ground, probe the A/C compressor clutch feed circuit in the relay connector.

Does the test lamp illuminate?

Go to Step 22

Go to Compressor Clutch Plate and Hub Assembly Removal

Repair the short to ground in the power feed circuit to the relay. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

Go to Step 27

Repair the short to ground in the compressor clutch feed circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

Go to Step 27

Repair the open or high resistance in the power feed circuit to the relay. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

Go to Step 27

Repair the open or high resistance in the A/C compressor clutch feed circuit. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

Go to Step 27

Repair the open or high resistance in the ground circuit of the A/C compressor clutch. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

Go to Step 27

Repair the short to power in the feed circuit of the A/C compressor clutch. Refer to Wiring Repairs in Wiring Systems.

Is the action complete?

Go to Step 27

Check for poor connections and terminal tension at the relay connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems .

Was a problem found and corrected?

Go to Step 27

Go to Step 24

Replace the relay.

Is the action complete?

Go to Step 27

Check for poor connections and terminal tension at the A/C compressor clutch connector. Refer to Testing for Intermittent Conditions and Poor Connections in Wiring Systems .

Was a problem found and corrected?

Go to Step 27

Go to Step 26

Replace the A/C compressor clutch coil. Refer to Compressor Clutch Plate and Hub Assembly Removal in HVAC.

Is the action complete?

Go to Step 27

Important: The following conditions must be met before continuing with this step:

•	The ambient air temperature must be more than 5°C (41°F).

•	The A/C pressure must be more than 35 psi (0.4 volt).

•	The engine coolant temperature must be less than 121°C (250°F).

Start the engine.
Turn the A/C on and off . Allow about 5 seconds between each transition.

Does the A/C compressor clutch engage and disengage?

System OK

Go to Step 2