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 Circuit Open
Diagnostic Fault Information
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
|---|---|---|---|---|
Antenna 14V Switched Supply Voltage | B1287 02 | B1287 04 | B1287 01 | -- |
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
| • | Radio is ON |
| • | The system voltage is at between 9 volts and 16 volts |
Conditions for Setting the DTC
A short to voltage, short to ground, or an open is seen on the remote enable circuit
Action Taken When the DTC Sets
Amplifier functions are disabled
Conditions for Clearing the DTC
| • | A current DTC clears when the condition for setting the DTC is no longer present |
| • | A history DTC clears after 100 malfunction- free ignition cycles |
Reference Information
Schematic Reference
Radio/Navigation System Schematics
Connector End View Reference
Entertainment/Communication Connector End Views
Description and Operation
Radio/Audio System Description and Operation
Electrical Information Reference
Scan Tool Reference
Circuit/System Verification
Radio ON, adjust the fade and balance control to verify audio is present at each individual channel.
Circuit/System Testing
- Ignition OFF, disconnect the C1 harness connector (UQ3) or C3 harness connector (U87) at the amplifier.
- Ignition ON, radio ON, test for 0.6-1.0 volts between the appropriate signal circuit terminal listed below and ground.
- If all circuits test normal, replace the audio amplifier.
| • | Terminal 11 C1 (UQ3) |
| • | Tterminal 7 C3(U87) |
| ⇒ | If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the radio. |
| ⇒ | If greater than the specified value, test the signal 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 radio or amplifier replacement
