GM Service Manual Online
For 1990-2009 cars only

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

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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.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, rear audio ON, test for 10.0-11.0 volts between the supply voltage circuit terminal 4 and ground.
  5. 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.
  6. 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