GM Service Manual Online
For 1990-2009 cars only

Test Description

The following numbers refer to the steps in the table.

  1. This step ensures that OnStar® can communicate with the vehicle and that the OnStar® GPS system is configured.

  2. This step checks proper operation of the GPS. The location that you are given from the OnStar® center is only an approximate location. There can be variance in this location. Do not mistake location variance for a inoperative GPS system.

  3. It is necessary to have a good ground on the antenna to filter out signal noise.

Step

Action

Value(s)

Yes

No

DEFINITION: This procedure is to diagnose the cause of the inoperative GPS receiver.

1

Did you perform the OnStar® Diagnostic System Check?

--

Go to Step 2

Go to OnStar System Check

2

  1. Turn ON the ignition, with the engine OFF.
  2. Activate the OnStar® Center button.
  3. Ask the operator to configure the vehicle.

Did you complete the repair?

--

Go to Step 2

Go to OnStar Call Center Unable to Configure OnStar (R) System

3

  1. Turn ON the ignition, with the engine OFF.
  2. Activate the OnStar® Center button.
  3. Ask the operator to give the vehicle's location.

Does the location given match you approximate location?

--

Go to Step 10

Go to Step 4

4

Is the GPS antenna installed in the proper location?

--

Go to Step 5

Go to Antenna Assembly Replacement

5

Inspect the GPS Antenna at the headliner.

Is the Grounding tab securely attached to the roof with the maximum area, as close as possible to the housing?

Go to Step 6

Go to Step 4

6

  1. Inspect the GPS antenna connection at VIU, adjust if necessary.
  2. Inspect the antenna cable for pinches, scrapes and cuts.

Is the antenna cable free from damage?

--

Go to Step 7

Go to Step 8

7

Test the ground circuit of the GPS antenna for a high resistance or an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 10

Go to Step 9

8

Replace the GPS antenna. Refer to Antenna Assembly Replacement .

Is the repair complete?

--

Go to Step 10

--

9

Replace the VIU. Refer to Vehicle Interface Unit and Vehicle Communication Unit Modules Replacement

Is the action complete?

--

Go to Step 10

--

10

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 3