GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 2006 🢒 DTS 🢒 DTC 🢒 DTC C0712

Circuit Description

The air suspension compressor motor is switched ON and OFF via an air suspension relay which is controlled by the air suspension control module. The air suspension control module provides a switched path to voltage whenever compressor activity is required. The air suspension control module monitors the compressor motor relay circuity to determine if the voltage level agrees with the command state.

DTC Descriptor

This diagnostic procedure supports the following DTC:

DTC C0712 Level Control Compressor Relay Circuit

This vehicle has DTCs which include DTC Symptoms. For more information on DTC Symptoms, refer to DTC Symptom Description .

DTC Symptom

DTC Symptom Descriptor

00

No Addition Information

Conditions for Running the DTC

The ignition is ON.

Conditions for Setting the DTC

Air suspension control module senses relay circuitry voltage does not agree with command state.

Action Taken When the DTC Sets
    • Air suspension functionality is suspended.
    • SERVICE SUSPENSION message is displayed.

Conditions for Clearing the DTC

The DTC will clear when the condition for setting the DTC is removed.

Diagnostic Aids

This DTC is set when the compressor relay circuitry is shorted to ground, voltage, and open.

Test Description

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

  1. During the air suspension relay operation, listen for an audible click. Command the ON and the OFF states. Repeat the commands as necessary.

    2.

  2. This step verifies that the air suspension control module is providing voltage to the air suspension relay.

    3.

  3. This step tests for an open in the ground circuit to the air suspension relay.

    4.

  4. This step tests for constant voltage to the air suspension relay.

Step

Action

Yes

No

Schematic Reference: Suspension Controls Schematics

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

Important: Be sure all doors are closed and the engine is running for this test.

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine ON.
  3. With a scan tool, command the compressor relay ON and OFF.

Does the compressor relay turn ON and OFF with each command?

Go to Diagnostic Aids

Go to Step 3

3

Important: Be sure all doors are closed and the engine is running for this test.

  1. Turn OFF the ignition.
  2. Disconnect the compressor relay.
  3. Turn ON the ignition, with the engine ON.
  4. Connect a test lamp to ground.
  5. Probe the control circuit of the compressor relay with a test lamp that is connected to ground.
  6. With a scan tool, command the compressor relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 4

Go to Step 5

4

Important: Be sure all doors are closed and the engine is running for this test.

  1. Connect a test lamp between the control circuit of the compressor relay and the ground circuit of the compressor relay.
  2. With a scan tool, command the compressor relay ON and OFF.

Does the test lamp turn ON and OFF with each command?

Go to Step 8

Go to Step 10

5

Does the test lamp remain illuminated with each command?

Go to Step 7

Go to Step 6

6

Test the control circuit of the compressor relay for a short to ground or an open. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 13

Go to Step 9

7

Test the control circuit of the compressor relay for a short to voltage. Refer to Circuit Testing and Wiring Repairs .

Did you find and correct the condition?

Go to Step 13

Go to Step 9

8

Inspect for poor connections at the compressor relay. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs .

Did you find and correct the condition?

Go to Step 13

Go to Step 11

9

Inspect for poor connections at the harness connector of the air suspension control module. Refer to Testing for Intermittent Conditions and Poor Connections and Wiring Repairs .

Did you find and correct the condition?

Go to Step 13

Go to Step 12

10

Repair the ground circuit of the air suspension relay. Refer to Wiring Repairs .

Did you complete the repair?

Go to Step 13

--

11

Replace the air suspension relay.

Did you complete the replacement?

Go to Step 13

--

12
  1. Replace the air suspension control module. Refer to Air Suspension Control Module Replacement for replacement.
  2. Perform the suspension position calibration procedure for the air suspension control module if necessary after checking trim height procedure. Refer to Suspension Position Calibration .

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.

Does the DTC reset?

Go to Step 2

System OK