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Chevrolet Silverado / GMC Sierra. Manual - part 2221
1. Ignition OFF, disconnect the antenna coax from the DRR.
2. Connect the EL-48028 to the DRR and place it on the roof of the vehicle. See Special
Tools.
3. Ignition ON, radio tuned to XM, verify XM reception has improved.
If the XM reception has not improved, replace the DRR.
4. Ignition OFF, disconnect the antenna coaxial cable from the DRR antenna base.
5. Test for less than 5 ohms between the two ends of the coax cable center conductor.
If greater than the specified range, replace the antenna coax cable.
6. Test for less than 5 ohms between the two ends of the coax cable outer shield.
If greater than the specified range, replace the antenna coax able.
7. Test for infinite resistance between the antenna coax center conductor and the outer shield.
If less than the specified range, replace the antenna coax cable.
8. If all circuits test normal, replace the digital radio antenna.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Mobile Telephone Digital Antenna Replacement
Control Module References for DRR replacement, setup, and programming
DTC B1287
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 Battery
DTC B1287 02
Amplifier Control Signal Circuit Short to Ground
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
DTC B1287 04
Amplifier Control Signal Circuit Open
Diagnostic Fault Information
Circuit/System Description
The amplifier receives PWM signals on the antenna 14V switch supply voltage circuit at varying
duty cycle percentages for controlling the ON and OFF functions of the amplifier. The radio
outputs a low duty cycle signal to produce an ON condition at the amplifier. The radio outputs a
high duty cycle signal to produce a OFF condition at the amplifier.
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
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Antenna 14V Switched Supply
Voltage
B1287 02
B1287 04
B1287 01
-
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
Component Connector End Views
Description and Operation
Radio/Audio System Description and Operation
Electrical Information Reference
Circuit Testing
Connector Repairs
Testing for Intermittent Conditions and Poor Connections
Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information
Circuit/System Verification
Radio ON, adjust the fade and balance control to verify audio is present at each individual
channel.
Circuit/System Testing
1. Ignition OFF, disconnect the X1 harness connector at the amplifier.
2. Radio ON, test for B+ between the signal circuit terminal 8 and ground.
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.
3. If all circuits test normal, replace the amplifier.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for radio or amplifier replacement
DTC B1288
Diagnostic Instructions
Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
Review Strategy Based Diagnosis for an overview of the diagnostic approach.
Diagnostic Procedure Instructions provides an overview of each diagnostic category.
DTC Descriptors
DTC B1288 01
Video Display Mode Control Signal Short to Battery
DTC B1288 02
Video Display Mode Control Signal Short to Ground
DTC B1288 04
Video Display Mode Control Signal Open Circuit
Diagnostic Fault Information
Circuit/System Description
The radio can control the video display mode on vehicles equipped with rear seat entertainment
(RSE) video. The radio varies a pulse with modulated (PWM) signal to the rear entertainment
video screen to command the display mode.
Conditions for Running the DTC
Ignition ON.
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
DVD Display B+
1
1
1
-
Radio ON Signal
1
1
1
-
Video Display Brightness
Signal
B1289 02
B1289 04
B1289 01
-
Video Display Mode Control
B1288 02
B1288 04
B1288 01
-
Video High Signal
1
1
1
-
Video Low Signal
1
1
1
-
DVD Display Ground
-
1
-
-
1. Video Entertainment System Inoperative.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
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