GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

DEFINITION: The ALC system does not raise the rear of the vehicle when weight is added to the rear of the vehicle.

1

Did you perform the ALC system check?

--

Go to Step 2

Go to Automatic Level Control System Operation Check

2

Important: Do NOT activate the compressor motor with the inflator switch. Perform the following steps with the compressor motor engaged ONLY by the trim height sensor.

With the compressor motor running, press the inflator fill valve core (if equipped) in order to inspect the air pressure at the inflator fill valve.

Is there air pressure/air flow at the inflator fill valve?

--

Go to Step 3

Go to Automatic Level Control System Leak Test

3

Connect a test light between the Inflator solenoid connector terminal A and terminal B.

Is the test light on?

--

Go to Step 5

Go to Step 4

4

Replace the inflator solenoid.

Does the customer concern still exist?

--

Go to Automatic Level Control System Operation Check

System OK

5

Disconnect the inflator switch electrical connector.

Is the test light still on?

--

Go to Step 6

Go to Step 9

6

Disconnect the inflator relay electrical connector.

Is the test light still on?

--

Go to Step 7

Go to Step 8

7

Inspect and repair circuit 1249 for a short to B+.

Does the customer concern still exist?

--

Go to Automatic Level Control System Operation Check System Check

System OK

8

Use a DMM in order to inspect circuit 1245 for a short to ground.

Is circuit 1245 is shorted?

--

Go to Step 10

Go to Step 11

9

Replace the inflator switch.

Does the customer concern still exist?

--

Go to Automatic Level Control System Operation Check System Check

System OK

10

Repair the short in circuit 1245.

Does the customer concern still exist?

--

Go to Automatic Level Control System Operation Check System Check

System OK

11

Replace the inflator relay.

Does the customer concern still exist?

--

Go to Automatic Level Control System Operation Check System Check

System OK