Buick Regal: DTC B127E (IO6)

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

Circuit/System Description

The infotainment display and controls are a separate component from the radio, combined into an assembly. The assembly is supplied battery voltage and ground from the vehicle harness. The human machine interface control module communicates digital video data for on-screen display through a dedicated cable containing the LVDS data circuits.

Control information, touch communications and dimming level for the display are communicated via a LIN serial data circuit to the human machine interface control module.

If the human machine interface control module detects the display is not responding to the output on the LVDS circuits, the human machine interface control module 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 continuously when the infotainment system is operating

Conditions for Setting the DTC

The human machine interface control module detects the display is not responding to the output on the LVDS circuits.

Action Taken When the DTC Sets

• The human machine interface control module sets this DTC
• No images are shown on the Info Display Module

Conditions for Clearing the DTC

• The human machine interface control module 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.

2. Verify the LVDS interface cable is properly connected at the P17 Info Display Module and the K74 Human Machine Interface Control Module connections and there is no damage to the cable or connections.

3. Ignition ON/Vehicle in Service Mode, infotainment system ON.

4. Verify the P17 Info Display Module does not display an image.

• If the P17 Info Display Module displays an image.

All OK.

• Go to next step: If the P17 Info Display Module does not display an image

5. Vehicle OFF/Ignition OFF.

6. Disconnect the LVDS interface cable from the P17 Info Display Module.

7. 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.

8. Disconnect the LVDS interface cable from the K74 Human Machine Interface Control Module.

Connect the EL-50334 - 14 Infotainment Test cable to the K74 Human Machine Interface Module.

9. Ignition ON/Vehicle in Service Mode, infotainment system ON.

10. Verify the P17 Info Display Module displays an image.

• If the P17 Info Display Module does not display an image

1. Replace the P17 Info Display Module. Connect all harness connectors.
2. Ignition ON/Vehicle in Service Mode, infotainment system ON.
3. Verify the P17 Info Display Module displays an image.
   • If the P17 Info Display Module still does not display an image, replace the K74 Human Machine Interface Control Module.
   • Go to next step: If the P17 Info Display Module displays an image.
4. All OK.

• Go to next step: If the P17 Info Display Module displays an image.

11. Replace the vehicle LVDS interface cable from the P17 Info Display Module to the K74 Human Machine Interface Module.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the repair.

• Refer to Radio Control Assembly Replacement (IOB) or Radio Control Assembly Replacement (IO5, IO6)
• Refer to Control Module References for human machine interface control module replacement, programming, and setup.

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