2022-2024 BMW X3/X4 Knee Air Bag Warning Light TSB

BMW has released Service Information Bulletin SIB 65 26 24, dated October 16, 2024, to address issues with the knee air bag system in certain 2022-2024 BMW X3 and X4 vehicles. This bulletin supersedes SI B65 01 22, which covered models produced prior to specific dates in July 2021.

Owners of affected vehicles may experience a persistent "red air bag warning light" in the instrument cluster, along with a "check control message (CCM) for the restraint system (Air bag)". These warnings indicate a potential fault within the knee air bag system.

Symptoms

If you own a 2022-2024 BMW X3 or X4, you might notice a persistent "red air bag warning light" illuminated in your vehicle's instrument cluster. This is typically accompanied by a "check control message (CCM) for the restraint system (Air bag)". These indicators point to a malfunction within the knee air bag system, which could affect the vehicle's safety features. This is a common symptom of a BMW X3 knee air bag warning light issue.

Fault Codes / DTCs

When diagnosing this issue, technicians may find one or more of the following fault codes stored in the Air Bag Control Module (ACSM):

• 930949: Knee airbag, driver: Short circuit to negative terminal
• 93094F: Knee airbag, front passenger: Short circuit to negative terminal
• 93094C: Knee airbag driver's side: Resistance too great
• 930952: Knee airbag, front passenger: Resistance too great

These codes specifically relate to electrical issues within the knee air bag circuits.

Cause

The root cause of the BMW X3 knee air bag warning light and associated fault codes is identified as chafing of the wiring harness. Over time, the wiring harness connected to the knee air bag(s) can rub against the metal support tubes of the instrument panel. This friction leads to chafing and damage to the wiring, causing electrical faults.

Important Warnings

BMW's Service Information Bulletin SIB 65 26 24 includes several critical instructions for technicians and important information for owners:

• "Neither the dashboard cover nor the knee air bags need to be removed." This clarifies that the repair does not require extensive disassembly of the dashboard.
• "Both replacement harnesses are to be installed, even if there is only a fault showing for one side." This ensures a complete and lasting repair, preventing future issues on the unaffected side.
• "The replacement harness does not need to follow the same exact path as the original." This provides flexibility during installation, as long as proper protection is maintained.
• Technicians must "Reference Wiring Diagram ‘Airbag firing circuits' SP0000061332 and confirm the wire color and pin number BEFORE cutting these 4 wires at the ACSM connector." This emphasizes the importance of precise wiring identification.
• "Important: The felt must be glued around the edge of the bracket!" This highlights a crucial step for preventing future chafing.

Repair Procedure Summary

The repair procedure outlined in SIB 65 26 24 involves several steps to address the chafed knee air bag wiring harnesses. The process begins with a vehicle test using ISTA diagnostics. Technicians must then gain access to the Air Bag Control Module (ACSM) by removing the center console, following Repair Instructions 51 16 165. Additionally, under-dash trim panels on both the driver's and passenger's sides are removed, referencing Repair Instructions 51 45 184 and 51 45 195.

Once access is established, the existing knee air bag harnesses are cut near their connectors (B81B for driver, B771B for passenger) and taped back. New repair wiring harnesses (part number 61 12 5 A56 386) are then run from the ACSM control module (A11*2B connector) to both knee air bags. The new harnesses are wrapped with abrasion-resistant fabric tape (part number 61 13 6 925 452) and felt strip (part number 54 34 7 248 700) is applied to potential chafe points, such as the dash support bracket, to prevent future damage.

Required Tools or Parts

To perform this repair, specific parts are required:

• 61 12 5 A56 386: Repair wiring for airbag system (Knee air bag) - Quantity 2
• 54 34 7 248 700: Felt strip, self-adhesive (130 x 40 x 3 mm) - Up to 4/cut to size
• 61 13 6 925 452: Fabric adhesive tape abrasion resistant (25 mm x 25 m) - Up to $5.00

Claim Information

This repair, identified by defect code 6112900300, is covered under the terms of the BMW New Vehicle Limited Warranty for Passenger Cars and Light Trucks. Technicians will use specific labor operations for diagnosis and repair, including 00 00 006, 00 00 556, 61 21 528, 51 16 665, and 00 72 587, to ensure proper reimbursement for their work.

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NHTSA ID: 11009001