For 1990-2009 cars

### Diagnostic Instructions

• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

• | Review Strategy Based Diagnosis for an overview of the diagnostic approach.

• | Diagnostic Procedure Instructions provides an overview of each diagnostic category.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Audio Signal (+) | 1 | 1 | 1 | 1
Audio Signal (-) | -- | 1 | 1 | 1
1. Cellular telephone conversation partner can not be heard

### Circuit/System Description

The mobile telephone control module sends the telephone call via a hardwired signal to the radio. The radio mutes the audio source and transmit the telephone call to the speakers.

### Reference Information

#### Schematic Reference

LINK

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Cellular Telephone Description and Operation

#### Electrical Information Reference

• | Circuit Testing

• | Connector Repairs

• | Testing for Intermittent Conditions and Poor Connections

• | Wiring Repairs

#### Scan Tool Reference

Control Module References for scan tool information

### Circuit/System Verification

1. Ignition ON, radio ON, adjust the radio balance and fade to each speaker.

⇒ | If any speaker does not operate properly, refer to LINK.

2. Ignition ON, Command the Audio Tone test ON and OFF with the scan tool, verify that a test tone turns ON and OFF

### Circuit/System Testing

Note: You must perform the Circuit/System Verification before proceeding with Circuit/System Testing.

1. Ignition OFF, disconnect the X1 connector at the K82 Mobile Telephone Control Module and the X1 connector at the A11 Radio.
2. Ignition ON, test for less than 0.3 V between the audio signal (+) circuit terminal 6 (X1) at the K82 Mobile Telephone Control Module and ground.

⇒ | If greater than the specified range, test the audio signal (+) circuit for a short to voltage.

3. Ignition ON, test for less than 0.3 V between the audio signal (-) circuit terminal 15 (X1) at the K82 Mobile Telephone Control Module and ground.

⇒ | If greater than the specified range, test the audio signal (-) circuit for a short to voltage.

4. Test for infinite resistance between the audio signal (+) circuit terminal 6 (X1) at the K82 Mobile Telephone Control Module and ground.

⇒ | If less than the specified range, test the audio signal (+) circuit for a short to ground.

5. Test for infinite resistance between the audio signal (-) circuit terminal 15 (X1) at the K82 Mobile Telephone Control Module and ground.

⇒ | If less than the specified range, test the audio signal (-) circuit for a short to ground.

6. Test for less than 5 Ω between the audio signal (+) circuit terminal 6 (X1) at the K82 Mobile Telephone Control Module and the audio signal (+) circuit terminal 20 (X1) at the A11 Radio.

⇒ | If greater than the specified range, test the audio signal (+) circuit for an open/high resistance.

7. Test for less than 5 Ω between the audio signal (-) circuit terminal 15 (X1) at the K82 Mobile Telephone Control Module and the audio signal (-) circuit terminal 6 (X1) at the A11 Radio.

⇒ | If greater than the specified range, test the audio signal (-) circuit for an open/high resistance.

8. Test for less than 5 Ω between the shield ground circuit terminal 5 (X1) at the K82 Mobile Telephone Control Module and the outer shield circuit.

⇒ | If greater than the specified range, test the shield ground circuit for an open/high resistance.

9. If all circuits test normal, replace the K82 Mobile Telephone Control Module and verify that the customer concern is not still present.

⇒ | If the customer concern is still present, replace the A11 Radio.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for mobile telephone control module or radio replacement, setup, and programming