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
--- | --- | --- | --- | ---
Cellular Microphone Signal | 1 | 1 | 1 | --
Cellular Microphone Drain | -- | 1 | -- | --
1. Microphone Inoperative - Caller Cannot Be Heard

### Circuit/System Description

Bluetooth ® wireless technology is a short-range communications technology intended to replace the cables connecting portable and/or fixed devices while maintaining high levels of security. Only vehicles with steering wheel controls will have Bluetooth ® functionality. In order to utilize the vehicle’s Bluetooth ® system, a Bluetooth ® equipped cellular phone is required. The bluetooth module is not connected to serial data and will not set DTCs. When a Bluetooth button keypress is made, the bluetooth module pulls the celular telephone signal to ground to mute all radio functions and transmit cellular telephone originated audio. After the audio system is muted, the cellular telephone signals are transmitted to the audio system on the cellular telephone voice signal circuit, and returned to the module on the cellular telephone voice low reference circuit.

### Reference Information

#### Schematic Reference

Cellular Telephone Schematics

#### 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 Testing

1. Ignition OFF, disconnect the harness connector at the Bluetooth microphone.
2. Test for less than 10 Ω between the drain circuit terminal 4 and ground.

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

3. Ignition ON, test for 7.2-9.2 V between the signal circuit terminal 1 and ground.

⇒ | If less than the specified range, test the circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the Bluetooth module.

⇒ | If greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the Bluetooth module.

4. If all circuit test normal, replace the Bluetooth microphone assembly.

### Repair Instructions

Perform the Diagnostic Repair Verification.

• | Bluetooth Microphone Replacement

• | Control Module References for Bluetooth module replacement, setup, and programming.