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 |
|---|---|---|---|---|
Amp Control | DTC B1287 02 | DTC B1287 04 | DTC B1287 01 | -- |
Circuit/System Description
The radio provides a radio audio mute signal circuit to control overall muting of remote non-serial data amplifiers. The amplifier receives PWM signals on the circuit at varying duty cycle percentages for controlling the muted and unmuted functions of the amplifier. A diagnostic sense circuit internal to the radio monitors the remote amp mute circuit for faults and sets the appropriate DTC when detected. The radio outputs a low duty cycle signal to produce an unmuted condition at the amplifier. The radio outputs a high duty cycle signal to produce a muted condition at the amplifier.
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 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
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 must be corrected. |
| • | A history DTC clears after 100 malfunction free ignition cycles. |
| • | The radio receives the clear code command from the scan tool. |
Diagnostic Aids
A short to ground may cause a buzz in the speakers when the radio is muted or turned OFF.
Reference Information
Schematic Reference
Radio/Navigation System Schematics
Connector End View Reference
Entertainment/Communication Connector End Views
Electrical Information Reference
Circuit/System Verification
Turn the radio on. Adjust the fade and balance control to test for audio sound from each individual channel.
Circuit/System Testing
- Ignition OFF, disconnect the C3 harness connector at the amplifier.
- Ignition ON, radio ON, test for 0.6-1.0 volts at the radio audio mute signal terminal 5 and ground.
- Press the phone mute button on the steering wheel control switch. Test for 6.0-8.0 volts at the radio audio mute signal terminal 5 and ground.
- If all circuits test normal, replace the amplifier.
| ⇒ | If less than the specified range, test the signal circuit for a short to ground or open/high resistance. If the circuit tests normal, replace the radio. |
| ⇒ | If greater than the specified range, test the signal circuit for a short to voltage. If the circuit tests normal, replace the radio. |
| ⇒ | If not within the specified range, replace the radio. |
Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for radio replacement, setup, and programming
