PRE-RELEASE
DTC B1287
| DTC B1287 |
| Diagnostic Instructions |
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Perform the
Diagnostic System Check - Vehicle
prior to using this diagnostic procedure.
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Review
Strategy Based Diagnosis
for an overview of the diagnostic approach.
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Diagnostic Procedure Instructions
provides an overview of each diagnostic category.
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| 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 | DTC B1287 02,** | DTC B1287 04,** | DTC 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.
| Conditions for Running the DTC |
The following are conditions that must be present in order for the radio to enable the diagnostics.
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The radio is in ACCESSORY, RUN, or RAP power mode.
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The system voltage is 9-16 V.
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The radio performs the test once during radio wakeup.
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| 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 |
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The condition must be corrected.
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A history DTC will be cleared after 100 malfunction-free ignition cycles.
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| 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
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Circuit Testing
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Connector Repairs
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Testing for Intermittent Conditions and Poor Connections
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Wiring Repairs
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Scan Tool Reference
Control Module References for scan tool information
| Circuit/System Verification |
Verify the audio system performance by adjusting the fade and balance of the speaker outputs.
| Circuit/System Testing |
| 1. |
Ignition OFF, disconnect the X3 harness connector at the T3 amplifier. |
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| 2. |
Ignition ON, start the radio, mute ON and test for 7.5 - 8.5 V between amplifier control circuit 11 and ground.
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| 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.
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| 4. |
If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the A11 radio.
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Mute OFF, test 7.5-8.5 for less than 1V between the amplifier control circuit terminal 11 and ground.
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If higher than the stated value, replace the radio A11.
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If all circuits test normal, replace the T3 amplifier.
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| Repair Instructions |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for radio and amplifier replacement, setup, and programming
