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Home >> Hummer >> 2008 >> H2 4D Utility Wagon >> Repair and Diagnosis >> External Pages >> Different car >> Section 48 (Air Suspension) >> Diagnostic Information and Procedures >> DTC C0712 >> Test Description

Test Description

WARNING: This page is about a different car, the 2007 Hummer H2. 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. 2:  During the air suspension relay operation, listen for an audible click. Command the ON and the OFF states. Repeat the commands as necessary.
  2. 3:  Verifies that the air suspension module is providing voltage to the air suspension relay.
  3. 4:  Tests for an open in the ground circuit to the air suspension relay.
  4. 5:  Tests for constant voltage to the air suspension relay.
DTC C0712

Step Action Yes No
Schematic Reference: Air Suspension 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 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 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.

    Probe the control circuit of the compressor relay with a test lamp that is connected to ground.

  5. 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 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 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 module. Refer to Control Module References .
  2. Perform the trim height calibration procedure for the air suspension module if necessary after check trim height procedure.
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
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