B1287
DTC B1287
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (Diagnostic System Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Strategy Based Diagnosis) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (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/System Description
The radio provides a remote amplifier mute output circuit to control overall muting of the remote amplifier. 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
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 at least 9 V and no more than 16 V.
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 be corrected.
* A history DTC clears after 100 malfunction-free ignition cycles.
* The radio receives the clear code command from the scan tool.
Reference Information
Schematic Reference
Radio/Navigation System Schematics (Radio/Navigation System Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
Description and Operation
Radio/Audio System Description and Operation (Radio/Audio System)
Electrical Information Reference
* Circuit Testing (Circuit Testing)
* Connector Repairs (Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (Wiring Repairs)
Scan Tool Reference
Control Module References (Programming and Relearning) for scan tool information
Circuit/System Verification
Radio ON, adjust the fade and balance control to verify audio is present at each individual channel.
Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the A11 radio.
2. Ignition ON, test for less than 1 V between the amplifier control circuit terminal 37 and ground.
• If greater than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the T3 audio amplifier.
3. Ignition OFF, test for greater than 20 Ohms between the amplifier control circuit terminal 37 and ground.
• If less than the specified value, test the circuit for a short to ground. If the circuit tests normal, replace the T3 audio amplifier.
4. Ignition OFF, disconnect the X3 harness connector at the T3 audio amplifier.
5. Test for less than 5 Ohms between the A11 radio X1 terminal 37 to the T3 audio amplifier X3 terminal 11.
• If greater than specified range, test the circuit for an open/high resistance.
6. If all circuits test normal, replace the A11 radio.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
Control Module References (Programming and Relearning) for radio and audio amplifier replacement, setup, and programming