GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 HUMMER 🢒 2004 🢒 H2 🢒 Suspension 🢒 Air Suspension 🢒 DTC C0631

Circuit Description

The Air Suspension Sensor provides a signal voltage between 0.3 and 4.7 volts to the Air Suspension Module. This signal voltage represents the wheel's position relative to the body. The Air Suspension Module provides a 5 volt reference and a low reference to the sensor.

Conditions for Running the DTC

At power-up and continuous when ignition is activated.

Conditions for Setting the DTC

Air Suspension Module senses a suspension sensor voltage below 0.3 volts or above 4.7 volts.

Action Taken When the DTC Sets
    • Air Suspension functionality is suspended.
    • SERVICE AIR 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 for a high or low signal to the Air Suspension Module from the Air Suspension Sensor-RR.

Test Description

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

  1. Checks the Air Suspension Sensor-RR data parameter.

    2.

  2. Tests for the proper operation of the circuit in the high voltage range.

    3.

  3. Tests for the proper operation of the circuit in the low voltage range. If the fuse in the jumper opens upon performing this test, the signal circuit has a short to voltage.

    4.

  4. Tests for a short to ground in the 5 volt reference circuit.

    5.

  5. Test the 5 volt reference circuit for the Air Suspension Sensor-RR.

Step

Action

Values

Yes

No

Schematic Reference: Suspension Controls Schematics

1

Did you perform the Air Suspension System Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Air Suspension

2

  1. Install a scan tool.
  2. Turn ON the ignition, with the engine OFF.
  3. With a scan tool, observe the Right Height Sensor parameter in the data list for the Air Suspension Module.

Is the Right Height Sensor parameter within the specified range?

0.3-4.7 V

Go to Diagnostic Aids

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the Air Suspension Sensor-RR.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Right Height Sensor parameter.

Is the Right Height Sensor parameter more than the specified value?

0.3 V

Go to Step 4

Go to Step 8

4

  1. Turn OFF the ignition.
  2. Connect a 3-ampere fused jumper wire between the signal circuit of the Air Suspension Sensor-RR and the low reference circuit of the Air Suspension Sensor-RR.
  3. Turn ON the ignition, with the engine OFF.
  4. With a scan tool, observe the Right Height Sensor parameter.

Is the Right Height Sensor parameter less than the specified value?

0.3 V

Go to Step 5

Go to Step 9

5

  1. Turn OFF the ignition.
  2. Disconnect the fused jumper wire.
  3. Turn ON the ignition, with the engine OFF.
  4. Test the 5 volt reference circuit voltage of the Air Suspension Sensor-RR.

Is the Right Height Sensor 5 volt reference voltage greater than the specified value?

4.7 V

Go to Step 7

Go to Step 6

6

Test the 5 volt reference circuit of the Air Suspension Sensor-RR for a short to ground. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

7

Test the 5 volt reference circuit of the Air Suspension Sensor-RR for one of the following conditions:

    • A short to voltage
    • A high resistance
    • An open

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 11

8

Test the signal circuit of the Air Suspension Sensor-RR for a short to voltage. Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

9

Test the signal circuit of the Air Suspension Sensor-RR for one of the following conditions:

    • A short to voltage
    • A high resistance
    • An open

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 10

10

Test the low reference circuit of the Air Suspension Sensor-RR for one of the following conditions:

    • A high resistance
    • An open

Refer to Circuit Testing and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

11

Inspect for poor connections at the harness connector of the Air Suspension Sensor-RR. Refer to Testing for Intermittent Conditions and Poor Connections and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 13

12

Inspect for poor connections at the harness connector of the Air Suspension Module. Refer to Testing for Intermittent Conditions and Poor Connections and to Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 14

13

Replace the Air Suspension Sensor-RR. Refer to Air Spring Leveling Sensor Replacement .

Did you complete the replacement?

--

Go to Step 15

--

14

Important: Always perform the check trim height procedure after Air Suspension Module replacement.

  1. Replace the Air Suspension Module. Refer to Module Assembly Electronic Suspension Control Replacement .
  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 15

--

15
  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