Chevrolet Silverado / GMC Sierra. Service manual — part 2220

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

Radio ON, adjust the fade and balance controls on the radio to test all four channels individually.
Each of the four channels should produce clear and even sound.

Circuit/System Testing

Without Amplifier

1. Ignition OFF, disconnect the harness connector at the appropriate speaker.

2. Radio ON, test for 5.0-7.5 volts between the signal circuit terminal A and ground.

If greater than the specified range, test the signal circuit for a short to voltage. If the
circuit tests normal, replace the radio.

If less than the specified range, test the signal circuit for a short to ground or an
open/high resistance. If the circuit tests normal, replace the radio.

3. Test for 5.0-7.5 volts between the signal circuit terminal B and ground.

If greater than the specified range, test the signal circuit for a short to voltage. If the
circuit tests normal, replace the radio.

If less than the specified range, test the signal circuit for a short to ground or an
open/high resistance. If the circuit tests normal, replace the radio.

4. If all circuits test normal, test or replace the speaker.

With Amplifier

1. Ignition OFF, disconnect the X1(except UQS) or X4(UQS)and X3 harness connectors at

the amplifier.

2. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below

and ground.

Left front door or tweeter - Connector X2, terminal 3

IMPORTANT: The DTC can be set by either the radio or the amplifier. If the DTC

was set by the radio, diagnose suspect audio input circuits to the
speakers or the amplifier (if equipped). Diagnose audio input
signals to the speakers from the amplifier if the DTC was set by
the amplifier.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Right front door or tweeter - Connector X2, terminal 1

Left rear speaker - Connector X2, terminal 7

Left rear subwoofer - Connector X3, terminal 3

Right rear speaker - Connector X2, terminal 5

Right rear subwoofer - Connector X3, terminal 2

If greater than the specified range, test the signal circuit for a short to voltage. If the
circuit tests normal, replace the radio.

If less than the specified range, test the signal circuit for a short to ground or an
open/high resistance. If the circuit tests normal, replace the radio.

3. Radio ON, test for 5.0-7.5 volts between the appropriate signal circuit terminal listed below

and ground.

Left front door or tweeter - Connector X2, terminal 4

Right front door or tweeter - Connector X2, terminal 2

Left rear speaker - Connector X2, terminal 8

Left rear subwoofer - Connector X3, terminal 7

Right rear speaker - Connector X2, terminal 6

Right rear subwoofer - Connector X3, terminal 6

If greater than the specified range, test the signal circuit for a short to voltage. If the
circuit tests normal, replace the radio.

If less than the specified range, test the signal circuit for a short to ground or an
open/high resistance. If the circuit tests normal, replace the radio.

4. If all circuits test normal, replace the amplifier.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Speaker Replacement Reference

Control Module References for Amplifier and Radio replacement, setup, and
programming

DTC B1259

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.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

Diagnostic Procedure Instructions provides an overview of each diagnostic category.

DTC Descriptors

DTC B1259 02

Antenna Ground Circuit Short to Ground

DTC B1259 05

Antenna Ground Circuit Short to Battery or Open

Circuit/System Description

The digital radio receiver (DRR) receives digital radio information from a specific digital radio
antenna located on the outside of the vehicle. The DRR is connected to the digital radio antenna
via a shielded coaxial cable. The antenna cable also provides a path for DC current for powering
the antenna.

Conditions for Running the DTC

Radio ON.

Battery voltage must be between 9-16 volts.

Conditions for Setting the DTC

B1259 02

The DTC will set when the DRR detects a short to ground in the antenna ground circuit.

B1259 05

The DTC will set when the DRR detects a short to voltage or an open/high resistance in the
antenna ground circuit.

Actions Taken When the DTC Sets

Digital radio reception may be poor or not available.

The radio displays "No XM Signal" or "Check Antenna".

Conditions for Clearing the DTC

The condition responsible for setting the DTC no longer exists.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado

A history DTC will clear once 100 consecutive malfunction-free ignition cycles have
occurred.

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

Circuit Testing

Connector Repairs

Testing for Intermittent Conditions and Poor Connections

Wiring Repairs

Scan Tool Reference

Control Module References for scan tool information

Special Tools

EL-48028 Digital Radio Test Antenna. See Special Tools.

Circuit/System Testing

IMPORTANT:

Ensure the vehicle is outside in an area with an unobstructed
view of the southern sky. Turn XM radio ON. Tune the radio to
satellite channel 1. XM reception should be clear.

Contact XM radio services at 1-800-852-9696 to verify the
customers account status or possible network problems.

2008 Chevrolet Silverado 1500

2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis

Silverado, Sierra & Silverado