GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Cellular Telephone Schematics

1

Did you perform Diagnostic System Check - Cellular Communication ?

Go to Step 2

Go to Diagnostic System Check - Cellular Communication

2

  1. Dock the cellular telephone handset.
  2. Turn ON the ignition.
  3. Turn on the radio and set the radio volume.
  4. Attempt to place a call in hands-free mode.
  5. Attempt to place a call using the docked handset.

Does the system operate normally?

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

Go to Step 3

3

Test the cellular telephone audio through the handset earpiece and through the vehicle audio system.

Is the cellular telephone audio noisy through the handset earpiece only?

Go to Step 7

Go to Step 4

4

Is the audio also noisy when the radio or compact disk (CD) changer is on?

Go to Diagnostic System Check - Radio/Audio System in Entertainment

Go to Step 5

5

  1. Disconnect the cellular telephone module connector and the cellular telephone handset connector.
  2. Test the cellular telephone voice low reference circuit for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 6

6

Test the voice signal drain wire for a short to voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 7

7

Inspect for poor connections at the harness connector of the cellular telephone handset. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 8

8

Replace the handset and handset cord.

Did you find and correct the condition?

Go to Step 11

Go to Step 9

9

Inspect for poor connections at the harness connector of the cellular telephone module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 11

Go to Step 10

10

Replace the cellular telephone module. Refer to Cellular Telephone Module Replacement .

Did you complete the replacement?

Go to Step 11

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11

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3