2010 Cadillac Truck Escalade RWD V8-6.0L Hybrid Page 242
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
DTC B1277 1A
- Microphone 1 (LF) Input Signal Circuit Bias Level Out of Range
DTC B127C 01
- Microphone 2 (RF) Input Signal Circuit Short to Battery
DTC B127C 02
- Microphone 2 (RF) Input Signal Circuit Short to Ground
DTC B127C 04
- Microphone 2 (RF) Input Signal Circuit Open
DTC B127C 1A
- Microphone 2 (RF) Input Signal Circuit Bias Level Out of Range
