GM Service Manual Online
For 1990-2009 cars only

OnStar Microphone Malfuncation Gen. 4

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 Cellular Communication Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Cellular Communication

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 rear view mirror 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?

7 V

Go to Step 4

Go to Step 5

4

Measure the voltage from the Cellular Microphone Signal circuit to the drain wire.

Does the voltage measure greater than the specified value?

7 V

Go to Step 7

Go to Step 6

5

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 13

Go to Step 8

6

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 13

Go to Step 9

7

Test the drain wire for a short to ground.

Did you find and correct he condition?

--

Go to Step 13

Go to Step 10

8

  1. Leave the rearview mirror 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 13

Go to Step 9

9

Inspect for poor connections at the harness connector of the rear view mirror. 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 13

Go to Step 12

10

Inspect for poor connections at the harness connector of the Communication Interface 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 13

Go to Step 11

11

Replace the rear view mirror assembly. Refer to Inside Rearview Mirror Replacement in Stationary Windows.

Did you complete the replacement?

--

Go to Step 13

--

12

Important: Perform the OnStar® setup procedure.

Replace the VCIM. Refer to Communication Interface Module Replacement .

Did you complete the replacement?

--

Go to Step 13

--

13

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2

OnStar Microphone Malfuncation Gen. 5

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 Cellular Communication Diagnostic System Check?

--

Go to Step 2

Go to Diagnostic System Check - Cellular Communication

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 rear view mirror 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 4

Go to Step 5

4

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 7

Go to Step 6

5

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 13

Go to Step 8

6

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 13

Go to Step 9

7

Test the drain wire for a short to ground.

Did you find and correct the condition?

--

Go to Step 13

Go to Step 10

8

  1. Leave the rearview mirror 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 13

Go to Step 9

9

Inspect for poor connections at the harness connector of the rear view mirror. 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 13

Go to Step 12

10

Inspect for poor connections at the harness connector of the Communication Interface 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 13

Go to Step 11

11

Replace the rear view mirror assembly. Refer to Inside Rearview Mirror Replacement in Stationary Windows.

Did you complete the replacement?

--

Go to Step 13

--

12

Important: Perform the OnStar® setup procedure.

Replace the VCIM. Refer to Communication Interface Module Replacement .

Did you complete the replacement?

--

Go to Step 13

--

13

Operate the system in order to verify the repair.

Did you correct the condition?

--

System OK

Go to Step 2