2024 BMW Driver's Door Lock Ethernet Bus Fault

Symptoms of a Corrupted Ethernet Bus

Owners of affected BMW vehicles, including models like the F90 M5 Sedan, G01 X3 Sports Activity Vehicle, and G20 3 Series Sedan, may experience several issues related to an interrupted Ethernet bus of the Body Domain Controller (BDC). The primary symptoms include a loss of audio output, a non-functional rear view camera, or failures within the driver assistance systems. These problems typically manifest during automatic locking at approximately 10 mph, or immediately after the Central Locking button is activated. This indicates a problem with the 2024 BMW driver's door lock.

Associated Fault Codes

When the Ethernet bus is corrupted, specific permanent SAE fault codes may be stored in the vehicle's system, depending on the installed equipment. These codes indicate communication problems with various modules:

Code	Description
S 0219	No Communication possible with: Amplifier
S 0261	No Communication possible with: Camera-based driver assistance
S 0273	No Communication possible with: Headunit
S 0313	No Communication possible with: All-round vision camera
S 0386	No Communication possible with: Instrument Panel
S 0394	No Communication possible with: Telematics control unit

Cause of the Issue

The root cause of these communication failures is a voltage surge generated by the driver's door locking motor. This surge overloads the BDC-18 Ethernet controller, leading to the interruption of the Ethernet bus. This specific issue affects the 2024 BMW driver's door lock.

Diagnosis Procedure

To confirm the 2024 BMW driver's door lock issue, technicians should follow a specific diagnostic process as outlined in SIB 51 27 24:

1. Test Drive and Initial Check: Begin by test driving the vehicle. During this drive, verify that the Headunit settings have automatic locking activated.
2. Complaint Duplication: Attempt to reproduce the customer's complaint by cycling the door locks. This can be achieved either during automatic locking (when the vehicle reaches approximately 10 mph) or by manually pressing the Central locking button.
3. Further Analysis (If Not Reproducible): If the failure cannot be reproduced under these specified test conditions, additional fault analysis using ISTA (Integrated Service Technical Application) is required to pinpoint the issue.
4. Isolation Test: Once the complaint is successfully duplicated, disconnect the driver's door lock. Perform another test drive to confirm if the failure is isolated to this component. If the symptoms disappear after disconnecting the lock, it strongly suggests the driver's door lock is the source of the problem.

Repair Procedure Summary

If disconnecting the driver's door lock resolves the symptoms, the correction involves replacing the driver's door lock. The detailed repair procedure is found in BMW repair instructions, specifically "Removing and installing/replacing the door lock of the driver's door 51 21 092 | REP-REP-P-5121092". After the new lock is installed, technicians must perform an additional test drive. During this drive, the door locks should be cycled repeatedly, as outlined in the diagnostic conditions, to ensure the vehicle issue has been completely resolved.

Required Parts

For this repair, specific parts will be needed. Technicians should refer to ETK/AIR (Electronic Parts Catalog / Aftersales Information Research) to determine the exact part numbers based on the vehicle's VIN and specific equipment.

• System latch, left: Quantity 1
• Clip, Door panel: Quantity If applicable

Additionally, other small materials such as fluids, lubricants, one-time use screws, nuts, and seals, which are required by ISTA repair instructions, must be sourced from the Electronic Parts Catalog or other approved BMW Group resources. These items are invoiced separately under the Repair Code specified in this bulletin.

Warranty and Claim Information

This repair, identified by Repair Code 5121007900 ("Rotary latch lock/system lock, front incorrect connection /contact"), is covered under the terms of the BMW New Vehicle Limited Warranty for Passenger Cars and Light Trucks, or the BMW Certified Pre-Owned Program.

To claim this repair, the following labor operations and their corresponding allowances apply:

Labor Operation	Description
00 00 006	Carrying out vehicle test (Main work)
00 00 556	Carrying out vehicle test (Plusposition work)
61 21 528	Supporting voltage of the vehicle electrical system / recharging vehicle battery
61 00 006*	Carrying out vehicle diagnosis, ABL (Work time)
00 58 500*	Diagnosis Worktime Flat Rate
51 21 592	Removing and installing/replacing the door lock of the driver's door

Note that if a Main labor code is used for another repair, labor operation 00 00 556 (Plus code) should be used instead of 00 00 006, or these operations should be excluded if the vehicle test is part of another repair. Work time labor operations 61 00 006 and 00 58 500 are not considered Main labor operations. For documentation and claiming procedures related to diagnosis work time, technicians should refer to SI B01 01 20 or B01 07 20.

---

Source: NHTSA Manufacturer Communication SIB 51 27 24