GM Service Manual Online
For 1990-2009 cars only

Step

Action

Value(s)

Yes

No

Schematic Reference: OnStar Schematics

Connector End View Reference: Cellular Communication Connector End Views

DEFINITION: The OnStar® Call Center operator can clearly be heard but the operator is unable to hear the caller.

1

Did you perform the Vehicle Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Vehicle in Vehicle DTC Information

2

  1. Turn ON the ignition, with the engine OFF.
  2. Press the OnStar® Call Center button.
  3. Ask the OnStar® operator if your voice can clearly be heard.

Does the OnStar® operator hear your voice?

--

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

Go to Step 3

3

  1. Turn OFF the ignition.
  2. Disconnect the cellular microphone connector.
  3. Turn ON the ignition, with the engine OFF.
  4. Measure the voltage from the cellular microphone signal circuit to a good ground.

Does the voltage measure greater than the specified value?

9 V

Go to Step 5

Go to Step 6

4

Measure the voltage from the cellular microphone battery positive voltage circuit to a good ground.

Does the voltage measure greater than the specified value?

11 V

Go to Step 5

Go to Step 9

5

Measure the voltage from the cellular microphone signal circuit to the drain wire.

Does the voltage measure greater than the specified value?

9 V

Go to Step 8

Go to Step 7

6

Test the cellular microphone signal circuit for an open or short to ground. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 10

7

Test the drain wire for an open. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 11

8

Test the cellular microphone low reference for a short to ground.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

9

Test the cellular microphone battery positive voltage circuit for an open.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 12

10

  1. Leave the cellular microphone disconnected.
  2. Disconnect the VCIM connector C2.
  3. Test the cellular microphone signal circuit and drain wire circuit for a short together.

Did you find and correct the condition?

--

Go to Step 15

Go to Step 11

11

Inspect for poor connections at the harness connector of the cellular microphone. 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 15

Go to Step 14

12

Inspect for poor connections at the harness connector of the vehicle communication interface module (VCIM). 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 15

Go to Step 13

13

Replace the cellular microphone assembly. Refer to Mobile Telephone Microphone Replacement .

Did you complete the replacement?

--

Go to Step 15

--

14

Important: Perform the VCIM setup procedure.

Replace the VCIM. Refer to Communication Interface Module Replacement .

Did you complete the replacement?

--

Go to Step 15

--

15

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2