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 B1287 01: Amplifier Control Signal Circuit Short to BatteryDTC B1287 02: Amplifier Control Signal Circuit Short to Ground
DTC B1287 04: Amplifier Control Signal Open Circuit
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Amplifier B+ | 1 | 1 | -- | -- |
Amplifier Control | B1287 02 | B1287 04 | B1287 01 | -- |
Amplifier Ground | -- | 1 | -- | -- |
1. All speakers inoperative | ||||
Circuit/System Description
The radio provides a remote amplifier mute output circuit to control overall muting of remote amplifiers. The amplifier receives pulse width modulated (PWM) signals on the control circuit at varying duty cycle percentages for controlling muted and unmuted functions of the amplifier. Circuitry internal to the radio monitors the remote amplifier mute circuit for faults and sets the appropriate DTC when faults are detected.
Conditions for Running the DTC
| • | Ignition ON. |
| • | Radio ON. |
| • | Battery voltage must be between 9-16 volts. |
Conditions for Setting the DTC
The DTC will set when the radio detects a short to voltage, short to ground, or an open/high resistance in the amplifier control circuit 400 ms after the radio activates the remote enable circuit.
Action Taken When the DTC Sets
The radio sets the DTC and continues to output the correct muted or unmuted amplifier state based on the fault condition on the circuit.
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. |
Diagnostic Aids
A short to ground may cause a buzz in the speakers when the radio is muted or turned OFF.
Reference Information
Schematic Reference
Radio/Navigation System Schematics
Connector End View Reference
Description and Operation
Radio/Audio System Description and Operation
Electrical Information Reference
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
- Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
- Radio ON, test for 0.6-1.0 volts between the control circuit terminal 11 and ground.
- If all circuits test normal, replace the audio amplifier.
| ⇒ | If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. |
| ⇒ | If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the radio. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for Audio Amplifier or Radio replacement, setup, and programming
