B1287

DTC B1287

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



DTC Descriptors
DTC B1287 01
- Amplifier Control Signal Circuit Short to Battery

DTC B1287 02
- Amplifier Control Signal Circuit Short to Ground

DTC B1287 04
- Amplifier Control Signal Circuit Open




Diagnostic Fault Information






Circuit/System Description

The radio provides a remote amplifier mute output circuit to control overall muting of remote amplifiers (UQA without Y91 only). 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.
* 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 noise in the speakers when the radio is muted or turned OFF.


Reference Information
Schematic Reference

Radio/Navigation System Schematics (Radio/Navigation System Schematics)
Connector End View Reference

Component Connector End Views (Connector Views)
Description and Operation

Radio/Audio System Description and Operation (Radio/Audio System Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Testing

1. Ignition OFF, disconnect the X3 harness connector at the audio amplifier.
2. Ignition ON, radio ON, test for 0.6-1.0 volts between the control circuit terminal 11 and ground.

• If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the radio.


• 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.

3. If all circuits test normal, replace the audio amplifier.



Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Radio Speaker Amplifier Replacement (With RPO UQS) (Radio Speaker Amplifier Replacement (With RPO UQS))Radio Speaker Amplifier Replacement (With RPO UQA) (Radio Speaker Amplifier Replacement (With RPO UQA))
* Control Module References (Programming and Relearning) for Audio Amplifier Radio replacement, setup, and programming