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 does not hear you

### Circuit/System Description

The mobile telephone control module uses the microphone to allow driver communication with the cellular telephone. The cellular telephone is connected to the mobile telephone control module via Bluetooth.

### 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

Ignition ON, observe the scan tool Microphone Signal parameter. The reading should be between10 mV and 20 mV.

### Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the B24 Cellular Telephone Microphone
2. Ignition OFF, test for less than 5 Ω between outer shield and ground.

⇒ | If greater than the specified range, test the outer shield circuit for an open/high resistance. If the circuit tests normal, replace the K82 Mobile Telephone Control Module

3. Ignition OFF, test for less than 5 Ω between low reference circuit terminal 2 and ground.

⇒ | If greater than the specified range, test the low reference circuit for an open/high resistance. If the circuit tests normal, replace the K82 Mobile Telephone Control Module.

4. Ignition ON, test for 9-11 V between the signal circuit terminal 3 and ground.

⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the K82 Mobile Telephone Control Module.

⇒ | If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K82 Mobile Telephone Control Module

5. If all circuits test normal, replace the B24 Cellular Telephone Microphone.

### Repair Instructions

Perform the Diagnostic Repair Verification

• | Mobile Telephone Microphone Replacement

• | Control Module References