GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Cadillac 🢒 1998 🢒 DeVille 🢒 Suspension 🢒 Automatic Level Control 🢒 Height Sensor Operational Check

Step

Action

Value(s)

Yes

No

DEFINITION: This test checks the condition of the height sensor and the height sensor supply and ground circuits. This diagnostic procedure only applies to vehicles without Road Sensing Suspension.

1
  1. Disconnect the height sensor connector.
  2. Measure the voltage from the height sensor connector (vehicle side), terminal C to ground.

Is battery voltage measured?

Battery Voltage

Go to Step 3

Go to Step 2

2

Important: Ensure that the ALC circuit breaker is not tripped (open).

Repair the open in circuit 1340 (ORN) between the ALC MaxiFuse® Block and the height sensor.

Is the repair or replacement complete?

--

Go to Automatic Level Control System Operation Check

--

3

Measure the voltage from the height sensor connector (vehicle side), terminal C to the same connector, terminal A.

Is battery voltage measured?

Battery Voltage

Go to Step 5

Go to Step 4

4

Repair the open circuit condition in CKT 1050 (BLK).

Is the repair complete?

--

Go to Automatic Level Control System Operation Check

--

5
  1. Turn the ignition switch to the ON position.
  2. Measure the voltage from the height sensor connector (vehicle side), terminal D to the same connector, terminal A.

Is battery voltage measured?

Battery Voltage

Go to Step 7

Go to Step 6

6

Important: Ensure that the ELC fuse is not open (blown).

Repair the open circuit condition in CKT 2141 (BRN).

Is the repair complete?

--

Go to Automatic Level Control System Operation Check

--

7
  1. Check the height sensor connector for proper terminal contact.
  2. Connect the height sensor connector.
  3. Cycle ignition switch and return ignition switch to ON.

Does the air compressor operate for 3 to 5 seconds after an initial 35 to 55 second delay?

--

Go to Step 9

Go to Step 8

8

Replace the height sensor. Refer to Automatic Level Control Sensor Adjustment .

Is the replacement complete?

--

Go to Automatic Level Control System Operation Check

--

9
  1. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information. NOTE: The vehicle must be raised on a drive-on lift or be supported at the rear under the rear axle. Full vehicle weight must be on the rear axle.
  2. Disconnect the link from the position sensor.
  3. Move the height sensor arm up so that it is approximately 45 degrees above level (to the floor).

Does the air compressor run after the 17 to 27 second delay?

--

Go to Step 11

Go to Step 10

10

Replace the height sensor. Refer to Automatic Level Control Sensor Adjustment .

Is the replacement complete?

--

Go to Automatic Level Control System Operation Check

--

11

Move the height sensor down slowly until the air compressor stops.

Does the air compressor stop?

--

Go to Step 13

Go to Step 12

12

Replace the height sensor. Refer to Automatic Level Control Sensor Adjustment .

Is the replacement complete?

--

Go to Automatic Level Control System Operation Check

--

13

Move the height sensor arm down so that it is approximately 45 degrees below level (to the floor).

After a 17 to 27 second delay, does air escape from the air compressor as the vehicle begins to lower?

--

Go to Step 15

Go to Step 14

14

Replace the height sensor. Refer to Automatic Level Control Sensor Adjustment .

Is the replacement complete?

--

Go to Automatic Level Control System Operation Check

--

15

Adjust the height sensor. Refer to Automatic Level Control Sensor Adjustment .

Is the adjustment complete?

--

Go to Automatic Level Control System Operation Check

--