DTC B1287
Diagnostic Instructions
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. The radio
monitors the amp control circuit for faults.
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 ist 9-16
V. |
| • |
The radio performs the test
once during wakeup. |
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
| • |
The condition must be
corrected. |
| • |
A history DTC clears after 100
malfunction-free ignition cycles. |
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
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Testing
|
Note: To prevent
misdiagnosis, the door chime must be OFF during testing. Ensure the
driver door latch is closed during testing.
|
| 1. |
Ignition OFF, disconnect the
X3 harness connector at the T3 amplifier. |
| 2. |
Ignition ON, radio ON, mute
ON, test for 7.5-8.5 V between the amplifier control circuit
terminal 6 and ground. |
| ⇒ |
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. |
| ⇒ |
If greater than the specified range, test the
control circuit for a short to voltage. If the circuit tests
normal, replace the A11 radio. |
| 3. |
Mute OFF, test for less than 1
V between the amplifier control circuit terminal 6 and
ground. |
| ⇒ |
If greater than the specified range, replace the
A11 radio. |
| 4. |
If all circuits test normal,
replace the T3 amplifier. |
Repair Instructions
Perform the
Diagnostic Repair Verification after completing the diagnostic
procedure.
Control Module References for radio and amplifier replacement,
setup, and programming
|
