Buick Regal: DTC B127E (IOB)
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.
- Refer to Diagnostic Procedure Instructions for an overview of each
diagnostic category.
DTC Descriptor
DTC B127E 00
Front Video Display Output Signal Malfunction
DTC B127E 01
Front Video Display Output Signal Short to Battery
Diagnostic Fault Information
Circuit/System Description
The infotainment display and controls are separate components from the radio.
The components are
supplied battery voltage and ground from the vehicle harness. The radio
communicates digital video
data for on-screen display through a dedicated cable containing the LVDS data
circuits.
If the radio detects the display is not responding to the output on the LVDS
circuits, the radio sets the
DTC.
Conditions for Running the DTC
- Ignition is ON or in the ACC position
- The system voltage is 9-16 V
- The infotainment system is ON
- The test is run once every 14 ms when the infotainment system is
operating
Conditions for Setting the DTC
The radio detects the display is not responding to the output on the LVDS
circuits.
Action Taken When the DTC Sets
- The radio sets this DTC
- No images are shown on the info display module
Conditions for Clearing the DTC
- The radio detects a properly synced digital video signal.
- A history DTC will clear once 50 consecutive malfunction-free ignition
cycles have occurred.
Reference Information
Schematic Reference
Radio/Navigation System Wiring Schematics (IOB) , Radio/Navigation System
Wiring Schematics
(IOR) or Radio/Navigation System Wiring Schematics (IO5/IO6) , or
Radio/Navigation System
Wiring Schematics (IOS/IOT).
Connector End View Reference
Component Connector End View Index
Description and Operation
Radio/Audio System Description and Operation (IO6) , Radio/Audio System
Description and Operation (IOB) , or Radio/Audio System Description and
Operation (IOS/IOT/IOU).
Electrical Information Reference
- Refer to Circuit Testing
- Refer to Connector Repairs
- Refer to Testing for Intermittent Conditions and Poor Connections
- Refer to Wiring Repairs
Scan Tool Reference
Control Module References for scan tool information.
Special Tools
- EL-50334 - 2 Type A female to Mini B male USB Cable
- EL-50334 - 14 Infotainment Test Cable
Circuit/System Testing
1. Vehicle OFF/Ignition OFF, disconnect the X1 harness connector at the P17
Info Display Module.
2. Test for infinite resistance between the signal circuits listed below and
ground:
- Radio display LVDS lock signal circuit terminal 5
- Radio display LVDS error signal circuit terminal 6
- If less than infinite resistance
Repair the short to ground on the circuit.
- Go to next step: If infinite resistance
3. Reconnect the X1 harness connector at the P17 Info Display Module.
4. Disconnect the LVDS interface cable from the P17 Info Display Module.
5. Connect the EL-50334-2 Type A female to Mini B male USB Cable to the P17 Info
Display
Module. Connect the EL-50334-14 Infotainment Test Cable to the adapter.
6. Disconnect the LVDS interface cable from the A11 Radio. Connect the EL-50334
- 14
Infotainment Test cable to the A11 Radio.
7. Ignition ON/Vehicle in Service Mode, infotainment system ON.
8. Verify DTC B127E is not set as current.
- If DTC B127E is set as current
- Replace the P17 Info Display Module. Connect all harness connectors.
- Ignition ON, infotainment system ON.
- Verify DTC B127E is not set as current.
- If DTC B127E is still set as current, replace the A11 Radio.
- Go to next step: If DTC B127E is not set.
- All OK.
- Go to next step: If DTC B127E is not set as current.
9. Replace the vehicle LVDS interface cable from the P17 Info Display Module
to the A11 Radio.
Repair Instructions
Perform the Diagnostic Repair Verification after completing the repair.
- Refer to Control Module References for replacement, programming, and
setup.
READ NEXT:
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.
Refe
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.
Refe
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.
Refe
SEE MORE:
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.
DTC Descriptors
D
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