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Chevrolet Silverado / GMC Sierra. Manual - part 2230
5. Test for less than 5 ohms of resistance at the antenna coax center conductor from end to end.
If greater than specified value, replace the antenna coax cable.
6. Test for infinite resistance between the antenna coax center terminal and the outer shield.
7. If coax cable tests normal, test or replace the navigation antenna.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Mobile Telephone Digital Antenna Replacement
Control Module References for VCIM replacement, setup, and programming
ONSTAR MICROPHONE INOPERATIVE - CALLER CANNOT BE HEARD
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.
Diagnostic Fault Information
Circuit/System Description
The communication interface module (CIM) provides the cellular microphone with a supplied
voltage on the cellular microphone signal circuit. When the microphone is in use, voice data from
the user is sent back to the CIM on the signal circuit. The CIM provides a ground for the
microphone via the drain wire.
Reference Information
Schematic Reference
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Cellular Microphone Signal
B2455 04
B2455 04
B2455 04
-
Cellular Microphone Low
Reference
-
B2455 04
1
-
1. OnStar Microphone Inoperative - Caller Cannot Be Heard
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
OnStar Schematics
Connector End View Reference
Component Connector End Views
Description and Operation
OnStar 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
1. Ignition OFF, disconnect the harness connector at the cellular microphone.
2. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
3. Ignition ON, test for 9.5-10.5 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 CIM.
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 CIM.
4. Test for test for 9.5-10.5 volts between the signal circuit terminal B and the drain circuit
terminal A.
If less than the specified range, test the drain circuit for a short to voltage or an
open/high resistance. If the circuit tests normal, replace the CIM.
5. If all circuits test normal, replace the cellular microphone.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
Mobile Telephone Microphone Replacement
Control Module References for CIM replacement, setup, and programming
NAVIGATION SYSTEM - VOICE RECOGNITION INOPERATIVE
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
OnStar 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
Circuit/System Testing
1. Verify the OnStar® voice recognition is operating normally.
If the OnStar® voice recognition is inoperative, refer to OnStar Microphone
Inoperative - Caller Cannot Be Heard.
2. Ignition OFF, disconnect the radio harness connector X1 and VCIM harness connector X3.
3. Test for less than 1 volt on the voice recognition audio signal circuit radio harness connector
terminal 4 and ground.
If greater than specified value, repair short to voltage.
4. Test for greater than 1 ohm between the voice recognition audio signal circuit radio harness
connector terminal 4 and ground.
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
If less than specified value, repair short to ground.
5. Test for less than 1 ohm between the voice recognition audio signal circuit radio harness
connector terminal 4 and the voice recognition audio signal circuit VCIM harness connector
terminal 2.
6. If greater than specified value, repair open circuit.
7. Test for less than 1 volt on the voice recognition audio low reference circuit radio harness
connector terminal 5 and ground.
If greater than specified value, repair short to voltage.
8. Test for greater than 1 ohm between the voice recognition audio low reference circuit radio
harness connector terminal 5 and ground.
If less than specified value, repair short to ground.
9. Test for less than 1 ohm between the voice recognition audio low reference circuit radio
harness connector terminal 5 and the voice recognition audio low reference signal circuit
VCIM harness connector terminal 4.
If greater than specified value, repair open circuit.
10. If all circuits test normal, replace the radio.
Repair Procedures
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
Control Module References for radio replacement, setup, and programming
NO (OR NOISY) ONSTAR AUDIO
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.
Diagnostic Fault Information
Circuit
Short to
Ground
Open/High
Resistance
Short to
Voltage
Signal
Performance
Cellular Telephone Voice
Signal
1
1
1
-
Cellular Telephone Voice
-
1
-
-
2008 Chevrolet Silverado 1500
2008 ACCESSORIES & EQUIPMENT Cellular, Entertainment, and Navigation - Cab & Chassis Sierra, Cab & Chassis
Silverado, Sierra & Silverado
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