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July 26, 2025 Service bulletin

Hand detection system not operating correctly / vehicles with code 266 Fault message in instrument...

Mercedes-Benz technical service bulletin LI46.10-P-078012 for 2023-2025 Mercedes-Benz GLC 300, 2020-2024 Mercedes-Benz GLE 350 and 2025 Mercedes-Benz GLS 450 4matic and others.

Bulletin number
LI46.10-P-078012
Component
Electrical system
Summary
Complaint Hand detection system not operating correctly / vehicles with code 266 Fault message in instrument cluster: "Active Emergency Stop Assist not available" "Active Lane Keeping Assist not available" Cause Possible causes: the hand detection mat, the hand detection control unit, the contacts and the steering wheel harness. Remedy In the event of a customer complaint and fault code in IDC control unit: U186B29 in IDC223 or fault code U0429E0, U042941, U042929, U042902, U0429E1 in IDC213 or fault code in HOSWD control unit: B1E7614 Test: Please perform the new SCN coding for HOSWD control unit (N179/1) (available since May 2025). Please flash the IDC (N62/4) software A223 902 75 37 (only applies to HOSWD223). Erase fault memory Remedy: Switch on ignition without touching the steering wheel. If after 10 seconds without touching the steering wheel, one of the two fault messages appears in the IC: Please check contacts and feed lines in the steering wheel by means of visual inspection for damage, crimped connections, loose connections, etc. (example in picture 2 and 3). If there is visible damage -> replace steering wheel electronics or feed lines. If there is no visible damage -> Proceed to replace the steering wheel. If no yellow message appears in the instrument cluster within 10 seconds: Please grab the steering wheel all the way round, including the 6 o'clock chrome molding, with both hands (see picture 1). If the fault is triggered by grabbing the steering wheel rim or pressing on the 6 o'clock clasp, check contacts and feed lines in the steering wheel by means of visual inspection for damage, crimped connections, loose connections, etc. (example in picture 2 and 3). Check ground connections (screw connections and cable to steering wheel rim); if necessary tighten screws/bolts and check for corrosion (Picture 4). If there is visible damage -> replace steering wheel electronics or feed lines. If no fault is visible -> Proceed to replace the steering wheel. In the event of a customer complaint and further fault code in HOSWD: B1E7713: Check ground connections (screw connections and cable to steering wheel rim); if necessary tighten screws/bolts and check for corrosion (Picture 4). B1F1F04: Check hand detection system control unit; if necessary swap with donor vehicle (ensure that the HW part numbers are identical).

Owners of these vehicles have filed 121 complaints in the electrical category.

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