GM Service Manual Online
For 1990-2009 cars only

Circuit Description

The compressor receives a refrigerant compression demand signal from the air conditioning amplifier. Based on this signal, the compressor changes the amount of compressor output.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC B1451 Compressor Solenoid Circuit

Conditions for Running the DTC

This DTC shall run when the ignition is On.

Conditions for Setting the DTC

Open or short in solenoid of the externally changeable compressor circuit.

Action Taken When the DTC Sets

The A/C compressor will be disabled.

Conditions for Clearing the DTC

The DTC will clear when conditions for setting the DTC have been repaired.

Step

Action

Value(s)

Yes

No

Schematic Reference: HVAC Schematics

Connector End View Reference: Component Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

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Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Turn OFF ignition.
  2. Disconnect the A/C compressor solenoid connector.
  3. Measure the resistance between connector B7 terminal 1 and body ground.

Is the resistance measured within the specified values?

Below 1 Ohm

Go to Step 3

Go to Step 5

3

Measure the resistance between connector B7 terminal 1 and terminal 2 at approximately 20°C (68°F).

Is the resistance measured within the specified values?

10-11 Ohms

Go to Step 4

Go to Step 7

4

  1. Disconnect the A/C amplifier solenoid connector.
  2. Measure the resistance between the A/C amplifier connector E62 terminal 7 and the A/C compressor solenoid connector B7 terminal 2.
  3. Measure the resistance between the A/C amplifier connector E62 terminal 7 and body ground.

Is the resistance measured within the specified values?

E62 terminal 7 - B7 terminal 2 = Below 1 Ohm

E62 terminal 7 - body ground = 10 Kohms or higher

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Go to Step 8

Go to Step 6

5

Repair or replace harness or A/C compressor solenoid B7 connector.

Did you complete the repair or replacement?

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Go to Step 9

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6

Repair or replace harness of the A/C compressor solenoid B7 connector or the A/C amplifier E62 connector.

Did you complete the repair or replacement?

--

Go to Step 9

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7

Replace the A/C compressor.

Did you complete the replacement?

--

Go to Step 9

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8

Replace the A/C amplifier.

Did you complete the replacement?

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Go to Step 9

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9

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

Does the DTC reset?

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Go to Step 2

System OK