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 amp 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 radio monitors the amp control circuit for faults. When a fault is detected the radio sets the appropriate DTC.


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 volts and no more than 16 volts.



Conditions for Setting the DTC

The radio detects a fault on the Amp 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 Views)
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)



Circuit/System Verification

Verify the audio system performance by adjusting the fade and balance of the speaker outputs.


Circuit/System Testing

Ignition OFF, test the amplifier control and remote enable signal circuits for an open, a short to voltage, or a short to ground.

If the circuit tests normal, replace the radio.



Repair Instructions

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


Control Module References (Programming and Relearning)for radio replacement, setup, and programming