GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

1

  1. Disconnect the auto level control sensor.
  2. Using a test light, backprobe from the auto level control sensor harness connector terminal C to ground.

Is the test light on?

--

Go to Step 3

Go to Step 2

2

Replace the auto level control inflator relay. Refer to:

    •  Automatic Level Control Relay Replacement for long wheel base with HVAC
    •  Automatic Level Control Relay Replacement for long wheel base without HVAC
    •  Automatic Level Control Relay Replacement for short wheel base

Has repair been made and the system rechecked?

--

System OK

--

3

Using a test light, backprobe between the auto level control sensor harness connector terminal A and terminal C.

Is the test light on?

--

Go to Step 5

Go to Step 4

4

Repair the poor connection or open in circuit 1725 between the auto level control sensor harness connector terminal A and G401.

Has the repair been made and the system rechecked?

--

System OK

--

5

  1. Turn the ignition switch to RUN.
  2. Using a test light, backprobe between the auto level control sensor harness connector terminal A to ground.

Is the test light on?

--

Go to Step 7

Go to Step 6

6

Repair the poor connection or open in circuit 39 between the auto level control sensor harness connector terminal D and S337.

Has the repair been made and the system rechecked?

-

System OK

-

7

  1. Disconnect the auto level control sensor.
  2. Connect a 10 A fused jumper from the auto level control sensor harness connector terminal E to ground.

Is the exhaust solenoid on and venting air?

--

Go to Step 8

Go to Step 9

8

Replace the auto level control sensor. Refer to Automatic Level Control Sensor Link Replacement .

Has the repair been made and the system rechecked?

--

System OK

--

9

Check to see if the fuse in the jumper wire is blown.

Is the fuse in the jumper open?

--

Go to Step 10

Go to Step 11

10

Report short to B+ on circuit 320.

Has the repair been made and the system rechecked?

--

System OK

--

11

  1. Leave the 10 A fused jumper connected.
  2. Disconnect the auto level control air compressor connector.
  3. Using a test light, backprobe between the auto level control air compressor harness connector terminal B and terminal C.

Is the test light on?

--

Go to Step 12

Go to Step 13

12

Replace the auto level control air compressor. Refer to Air Compressor Replacement .

Has the repair been made and the system rechecked?

--

System OK

--

13

Check for a poor connection or open in circuit 320.

Is there a poor connection or open in circuit 320?

--

Go to Step 15

Go to Step 14

14

Repair the poor connection or open in circuit 1240 between the ELC fuse and the auto level control air compressor harness connector terminals A, C and E.

Has the repair been made and the system rechecked?

--

System OK

--

15

Repair the poor connection or open in circuit 320.

Has the repair been made and the system rechecked?

--

System OK

--