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.

### DTC Descriptors

DTC B1449 03: Remote Device Voltage Below Threshold
DTC B1449 07: Remote Device Voltage Above Threshold

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Infrared Module Voltage Signal | B1449 03 | B1449 03 | B1449 07 | --

### Circuit/System Description

The infrared module is supplied with 10.5 volts from the rear audio/HVAC module when the rear audio system is active. The infrared module is permanently grounded at G300.

### Conditions for Running the DTC

• | Ignition ON.

• | Battery voltage must be between 9-16 volts.

### Conditions for Setting the DTC

The DTC will set when the rear audio/HVAC module detects a short to voltage, short to ground, or an open/high resistance in the infrared module voltage signal circuit.

### Action Taken When the DTC Sets

The rear audio/HVAC module sets the DTC and the infrared module will be disabled.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | A history DTC will clear once 100 consecutive malfunction-free ignition cycles have occurred.

### Reference Information

#### Schematic Reference

Radio/Navigation System Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Video Entertainment System 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 infrared module.
2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal 12 and ground.

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

3. Ignition ON, rear audio ON, test for 10.0-11.0 volts between the supply voltage circuit terminal 4 and ground.

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

⇒ | If greater than the specified range, test the voltage supply circuit for a short to voltage. If the circuit tests normal, replace the rear audio/HVAC module.

4. If all circuits test normal, replace the infrared module.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Audio System Transceiver Module Replacement

• | Control Module References for Rear Audio/HVAC Module replacement, setup, and programming