2010 Cadillac Truck Escalade EXT AWD V8-6.2L Page 242
Cancellation Description and Operation)
Electrical Information Reference
* Circuit Testing (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Circuit
Testing/Circuit Testing)
* Connector Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic
Procedures/Connector Repairs/Connector Repairs)
* Testing for Intermittent Conditions and Poor Connections (See: Testing and Inspection/Component Tests and General Diagnostics/General
Electrical Diagnostic Procedures/Circuit Testing/Testing for Intermittent Conditions and Poor Connections)
* Wiring Repairs (See: Testing and Inspection/Component Tests and General Diagnostics/General Electrical Diagnostic Procedures/Wiring
Repairs/Wiring Repairs)
Scan Tool Reference
Control Module References (See: Testing and Inspection/Programming and Relearning) for scan tool information
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate microphone.
2. Ignition ON Radio ON, test for 0.47-2.75 V between the microphone (-) signal circuit terminal A and ground.
瀚慖f greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
瀚慖f less than the specified range, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the
amplifier.
3. Test for 5.75-8.03 V between the microphone (+) signal circuit terminal B and ground.
瀚慖f greater than the specified range, test the circuit for a short to voltage. If the circuit tests normal, replace the amplifier.
瀚慖f less than the specified range, test the circuit for an open/high resistance or a short to ground. If the circuit tests normal, replace the
amplifier.
4. If all circuits test normal, replace the appropriate microphone.
Repair Instructions
Perform the Diagnostic Repair Verification (See: Verification Tests) after completing the diagnostic procedure.
* Radio Volume Compensator Interior Noise Microphone Replacement (Floor Console) (See: Accessories and Optional Equipment/Radio,
Stereo, and Compact Disc/Automatic Volume Control/Service and Repair/Radio Volume Compensator Interior Noise Microphone
Replacement (Floor Console))Radio Volume Compensator Interior Noise Microphone Replacement (Headliner) (See: Accessories and
Optional Equipment/Radio, Stereo, and Compact Disc/Automatic Volume Control/Service and Repair/Radio Volume Compensator Interior
Noise Microphone Replacement (Headliner))
* Control Module References (See: Testing and Inspection/Programming and Relearning) for amplifier replacement, setup, and programming
B127D
DTC B1277, B127C, or B127D
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic System
Check - Vehicle) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Strategy Based Diagnosis) for an
overview of the diagnostic approach.
* Diagnostic Procedure Instructions (See: Testing and Inspection/Initial Inspection and Diagnostic Overview/Diagnostic Procedure
Instructions) provide an overview of each diagnostic category.
DTC Descriptors
DTC B1277 01
- Microphone 1 (LF) Input Signal Circuit Short to Battery
DTC B1277 02
- Microphone 1 (LF) Input Signal Circuit Short to Ground
DTC B1277 04
- Microphone 1 (LF) Input Signal Circuit Open
