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DTC B1287

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 Battery

DTC B1287 02: Amplifier Control Signal Circuit Short to Ground

DTC B1287 04: Amplifier Control Signal Circuit Open

Diagnostic Fault Information

Circuit

Short to Ground

Open/High Resistance

Short to Voltage

Signal Performance

Amplifier Control

B1287 02,**

B1287 04,**

B1287 01,*

-

* No audio output.

** 4 Channel unmute, possible noise in speakers when radio muted or turned off

Circuit/System Description

The radio amplifier control circuit provides varying pulse width modulated (PWM) signals to control overall muting of the amplifier. The PWM signals are varying duty cycle percentages ranging from 0-100 percent. A low duty cycle unmutes all amplifier channels and a high duty cycle mutes all amplifier channels. The amplifier control circuit will measure less than 1 V when the mute function is OFF, and approximately 8 V DC when at full mute. The radio monitors the amp control circuit for faults.

Conditions for Running the DTC

The following are conditions that must be present in order for the radio to enable the diagnostics.

    • The radio is in ACCESSORY, RUN, or RAP power mode.
    • The system voltage is 9-16 V.
    • The radio performs the test once during wakeup.

Conditions for Setting the DTC

The radio detects a fault on the amplifier control circuit 400 ms after radio activates the remote enable circuit.

Action Taken When the DTC Sets

Radio sets the DTC and continues to output correct state.

Conditions for Clearing the DTC
    • The condition must no longer be present.
    • A history DTC clears after 50 malfunction-free ignition cycles.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Radio/Audio 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

    Note: To prevent misdiagnosis, the door chime must be OFF during testing. Ensure the driver door latch is closed during testing.

  1. Vehicle OFF, disconnect the X2 harness connector at the T3 amplifier.
  2. Vehicle in Service Mode, radio ON, mute ON, test for 7.5-8.5 V between the amplifier control circuit terminal 12 and ground.
    3. ⇒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 A11 radio.
    ⇒If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.
  3. Mute OFF, test for less than 1 V between the amplifier control circuit terminal 12 and ground.
    4. ⇒If greater than the specified range, replace the A11 radio.
  4. If all circuits test normal, replace the T3 amplifier.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for radio and amplifier replacement, programming and setup

   


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