Chevrolet Silverado / GMC Sierra. Service manual — part 2235

Radio/Navigation System Schematics

Connector End View Reference

Component Connector End Views

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 Testing

Test or repair open, short to ground or short to voltage on the RSA ground circuit and battery
positive voltage circuit.

If all circuits test normal, replace the rear HVAC control module.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Rear Seat Audio Control Replacement

RADIO DISPLAYS CAL OR CAL ERR

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.

Reference Information

Schematic Reference

2008 Chevrolet Silverado 1500

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

Silverado, Sierra & Silverado

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

Circuit/System Testing

Ignition ON, with a scan tool, reprogram the radio.

If the radio still displays CAL ERR after performing the reprogramming procedure, replace
the radio.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Radio replacement, setup, and programming

RADIO DISPLAYS LOC, LOCKED, OR CODE

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.

2008 Chevrolet Silverado 1500

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

Silverado, Sierra & Silverado

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

Circuit/System Testing

Ignition ON, with a scan tool, reprogram the radio.

If the radio still displays LOCKED after performing the reprogramming procedure, replace
the radio.

Repair Procedures

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for Radio replacement, setup, and programming

RADIO POOR RECEPTION

Diagnostic Instructions

2008 Chevrolet Silverado 1500

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

Silverado, Sierra & Silverado

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.

Circuit/System Description

AM and FM radio reception is dependent on the following components:

Radio antenna

Coax cable between the radio antenna and the radio antenna module (if equipped).

Radio antenna module (if equipped)

Coax cable between the radio antenna module and the radio

Radio

Diagnostic Aids

Poor AM and FM radio reception is dependent on multiple influences, some of which may not be
vehicle related. Areas which have high RF traffic or block the signal path may cause a
degradation in radio reception. Radio reception may also be influenced by items within the
vehicle, but not part of the radio system. Such examples are aftermarket electrical accessories or
other items which may generated noise in the vehicle electrical system.

Diagnosing a poor reception concern will require a systematic approach to isolating the cause.
Individual components should each be tested before proceeding with any repair or replacement.

Using a Test Antenna

Use a test mast antenna to check for poor vehicle antenna operation. Disconnect the antenna coax
from the radio and plug the test antenna into the radio. Make sure the test antenna base is
grounded to the vehicle chassis and keep hands off the mast. Check radio reception in an area
away from electrical interferences. Tune to several weak and strong AM and FM stations. If the
radio reception improved, the problem exists with the vehicle antenna and/or lead-in cable.

Reference Information

Schematic Reference

Radio/Navigation System Schematics

Connector End View Reference

2008 Chevrolet Silverado 1500

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

Silverado, Sierra & Silverado