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 |
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Amplifier Control
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DTC B1287 02
1, 2 |
DTC B1287 04
1, 2 |
DTC B1287 01
1 |
-
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1. No audio output.
2. 4 Channel unmute, possible noise in speakers when radio muted or turned off |
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| 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%. A low duty cycle unmutes all amplifier channels and a high duty cycle mutes all amplifier channels. The radio monitors the amplifier 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.
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The radio is in ACCESSORY or RUN power mode.
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The system voltage is between 9-16 V.
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| Conditions for Setting the DTC |
The radio detects a fault on the Amplifier Control circuit 0.4 s 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 clear once 100 malfunction-free ignition cycles have occurred.
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The radio receives the clear code command from the scan tool.
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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 |
RPO Code UQA
| 1. |
Ignition OFF, disconnect the X1 harness connector at the A11 Radio.
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| 2. |
Ignition ON, test for less than 1 V between the radio audio mute signal terminal 37 and ground.
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| 3. |
If greater than the specified value, test the circuit for a short to voltage. If the circuit tests normal, replace the T3 Audio Amplifier.
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| 4. |
Ignition OFF, test for greater than 20 Ω between the radio audio mute signal terminal 37 and ground.
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| 5. |
If less than the specified value, test the circuit for a short to ground. If the circuit tests normal, replace the T3 Audio Amplifier.
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| 6. |
Ignition OFF, disconnect the X3 harness connector at the T3 Audio Amplifier.
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| 7. |
Test for less than 5 Ω between the signal circuit terminal 37 X1 at the A11 Radio harness connector and terminal 6 X3 at the T3 Audio Amplifier harness connector.
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| 8. |
If greater than specified range, test the circuit for an open circuit/high resistance.
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| 9. |
If all circuits test normal, replace the A11 Radio.
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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
