# U186B on the 2021 Mercedes\-Benz AMG GT

The bulletins listed name this code in NHTSA's summary, or are about the same components. A bulletin or a recall listed here may apply to the model year. None of it is a diagnosis.

This code is specific to a manufacturer and is not described here.

## Bulletins for this model year that name U186B

- [11035120](https://open.wenmarpro.com/bulletins/11035120), 2026-07-21: Complaint Hand detection system – malfunction / vehicles with code 266 Fault message in instrument cluster: "Active Emergency Stop Assist not available" "Active Lane Keeping Assist not available" "Active steering assist not available" Cause Possible causes: Hand detection mat, hand detection control unit, contacts, and electrical feed line. 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 Check: Please do not replace the HOSWD control unit. Please flash the new SW and perform the SCN coding for the HOSWD control unit \(N179/1\) \(available from July 2026\). The software can be flashed onto all HOSWD213 with HW number A0009011522 and all HOSWD223 with HW number A0009011422. Please also flash the SW for the IDC control unit \(N62/4\), if possible \(only applies to HOSWD223\). Erase fault memory Remedy: Turn on the ignition or start the engine without touching the steering wheel. If, after 10 seconds without touching the steering wheel, one of the three fault messages appears on the instrument cluster: Check the contacts and feed lines in the steering wheel by means of a visual inspection for damage, crimp connections, loose connections, etc. \(example in picture 2 and 3\). If there is visible damage \-\> replace the steering wheel electronics or the feed lines. If there is not any visible damage \-\> replace the steering wheel rim. If a yellow message does not appear on the instrument cluster within 10 seconds: Grasp the steering wheel fully with both hands, including the chrome molding at the 6 o'clock position \(see picture 1\). If the fault is triggered by grasping the steering wheel rim or pressing the clip at the 6 o'clock position, check the contacts and feed lines in the steering wheel by means of a visual inspection for damage, kinked connections, loose connections, etc. \(example in picture 2 and 3\). Check the ground connections \(screw connections and cables to the steering wheel rim\); if necessary, retighten the screws/bolts and check for corrosion \(picture 4\). If there is visible damage \-\> replace the steering wheel electronics or the feed lines. If there is not any visible damage: Replace the steering wheel rim. Please do not replace the HOSWD control unit. A TIPS case should be created if fault profile is unclear. In the event of a customer complaint and a further fault code in HOSWD: B1E7713: Check the ground connections \(screw connections and cables to the steering wheel rim\); if necessary, retighten the screws/bolts and check for corrosion \(picture 4\). B1F1F04: Check the control unit of the hand detection system; if necessary, replace this with the control unit from a donor vehicle \(make sure that the hardware part numbers are identical\).
- [11021143](https://open.wenmarpro.com/bulletins/11021143), 2025-08-01: 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 \(ensure that the HW part numbers are identical\).
- [11005334](https://open.wenmarpro.com/bulletins/11005334), 2024-07-30: 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 Test Procedure: Perform an initial quick test with freeze frame data. Save the N179 \- Hand detection system \(HE\) and N62/4 \- Driver assistance system \(SG\-FAS\) control unit logs. Note the fault frequency of fault codes set. Delete the N179 and N62/4 fault memory. Using both hands, "scan" the steering wheel all the way round, including the chrome molding at 6 o'clock \(see Picture 1\). Read out fault memory and follow steps below for any faults set. Remedy: Vehicles with control unit N179 \- Hand detection system \(HE\): B1E7614: Check contacts and wiring harness in steering wheel by carrying out a visual check for damage, pinched areas, loose connections, etc. \(examples in Figs. 2 and 3\); If no damage is noted replace the N135 \- Steering wheel electronics \(LRE\) and reassess. If fault code returns replace the steering wheel. Please check the wires and connections in the steering wheel. Afterwards, please check whether the complaint is caused by over torqued screws on steering wheel trim pieces. To do this, please loosen the screws slightly and reevaluate the situation. \(Picture 4\). P164456: Perform SCN coding. P1CA000: Perform an initial start\-up on the N179 hand detection control unit. Faults in N62/4 \- Driver assistance system \(SG\-FAS\) control unit with U186B29, U0429E0, U042941, U042929, U042902, U0429E1: If no fault is stored in the N179 control unit: Scan steering wheel as indicated in the test procedure and check whether the fault is reproducible. If no fault code is stored in the hand detection control unit, the fault codes in the driver assistance systems control unit are precautionary messages. Software for the N62/4 \- Driver assistance system \(SG\-FAS\) is in preparation to reduce erroneous messages in the driver display.