# Service bulletin B521125

A bulletin is a manufacturer's communication to its dealers, as NHTSA indexes it. The summary is NHTSA's. The document is the manufacturer's: read it at NHTSA. A bulletin is not a recall, and listing a model year does not mean every vehicle of it is concerned.

- Type: Service bulletin
- NHTSA id: 11022110
- Published by NHTSA: 2025\-08\-24
- Manufacturer's number: B521125
- Manufacturer's date: 2025\-08\-21
- NHTSA component: SEATS; ELECTRICAL SYSTEM

## NHTSA's summary

If the seat ventilation is deactivated via the switch or due to parking the vehicle, the fans in the seat cushionor under the seat cushion surface are unpleasantly loud. The fans speed up loudly twice and then turn off. The functionality of the fans is not impaired. This behavior only occurs after the vehicle had been programmed to I level S18A\- 25\-07\-520 and higher; upto, but not including S18A\- 25\-07\-551.

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2025/MC-11022110-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2025/MC-11022110-9999.pdf)

The document is the manufacturer's. This site does not hold it.

## Components

Electrical system, Seats

## Vehicles listed

- 2020 to 2025 BMW 840I

## Recalls for the same vehicles and component

- [25V644000](/recalls/nhtsa/25V644000.md), 2025-09-25: ELECTRICAL SYSTEM:STARTER ASSEMBLY
- [24V576000](/recalls/nhtsa/24V576000.md), 2024-08-01: ENGINE AND ENGINE COOLING:ENGINE:ENGINE CONTROL MODULE \(ECU/ECM\):SOFTWARE; ELECTRICAL SYSTEM:STARTER ASSEMBLY
- [23V099000](/recalls/nhtsa/23V099000.md), 2023-02-17: ELECTRICAL SYSTEM:SOFTWARE; VISIBILITY:POWER WINDOW DEVICES AND CONTROLS
- [20V761000](/recalls/nhtsa/20V761000.md), 2020-12-09: ELECTRICAL SYSTEM:12V/24V/48V BATTERY

## Other bulletins for the same vehicles and component

- [B110426](/bulletins/11035500.md), 2026-08-03, Service bulletin: ENGINE; ELECTRICAL SYSTEM. The manual starting of electronic engine oil level measurement from inside the vehicle, usually afterperforming an engine oil service task, is inoperative or it may lock up at between a 15% to 30% completionrate.
- [B840226](/bulletins/11035408.md), 2026-07-31, Service campaign: ELECTRICAL SYSTEM. Once the Telematics Module \(TCB2\) enters sleep mode, a BMW Data Services trigger for Remote Services\(remote engine start, lock/unlock/climate conditioning\) will not be able to reactivate the TCB2. Due to this issue, Remote Services will not function in the vehicle when parked and locked.
- [B520525](/bulletins/11014660.md), 2025-03-03, Service bulletin: ELECTRICAL SYSTEM. The customer states: The driver’s seat will not return to its last saved position. No seat memory. The heated seats settings in the menu are missing/different than in their previous BMW vehicle. They canno longer select, under the climate rules, at what temperature Fahrenheit the heated seats willautomatically turn on. Certain other “apps” and functions are not available The driver’s seat moves to an unknown memory position
- [B060425](/bulletins/11013098.md), 2025-01-25, Other: SEATS. FITTINGS RETURN
- [B512724](/bulletins/11010762.md), 2024-11-25, Service bulletin: ELECTRICAL SYSTEM. The Ethernet bus of the Body Domain Controller \(BDC\) is interrupted so that audio output, rear viewcamera, or the driver assistance systems fail. The symptoms begin to appear during auto locking at approx.10 mph, or after the Central Locking button is activated. Dependent upon vehicle equipment, the following permanent SAE faults may be stored in the vehicle: 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
- [B610321](/bulletins/10250893.md), 2024-03-02, Service bulletin: ELECTRICAL SYSTEM; FUEL SYSTEM, GASOLINE:STORAGE:EVAPORATIVE EMISSIONS:CANISTER; ELECTRICAL SYSTEM:SOFTWARE. SITUATION BMW AG is conducting a Voluntary Emissions Recall \(effective April 23, 2021\) on a certain Model Year 2020 \- 2021 BMW vehicles that were produced between August 13, 2019 and December 11, 2020. Do not deliver to a customer, a New, Certified Pre\-Owned or Used vehicle subject to an emissions recall, until the vehicle is repaired. Do not use or sell replacement equipment/parts subject to an emissions recall. The 12 V battery’s dual storage system \(DSS\) may contain a software error which intermittently causes a continuous resetting of the microcontroller and communication failure. The error is displayed by a red Check Control message.
- [B660720](/bulletins/10250601.md), 2024-03-02, Service bulletin: EQUIPMENT; ELECTRICAL SYSTEM. The functionality of the left rear SRR sensor could be reduced which would display the Driving Assistance Check Control Message.
- [B660820](/bulletins/10250600.md), 2024-03-02, Service bulletin: ELECTRICAL SYSTEM; EQUIPMENT. The functionality of the right rear SRR sensor could be reduced which would display the "Driving Assistance"\- Check Control Message.
- [B510819](/bulletins/10249437.md), 2024-02-01, Service bulletin: VISIBILITY:POWER WINDOW DEVICES AND CONTROLS; ELECTRICAL SYSTEM. The basic conditions for initializing the power windows are not met.
- [B610524](/bulletins/10249032.md), 2024-02-01, Service bulletin: EQUIPMENT:ELECTRICAL:INFOTAINMENT; ELECTRICAL SYSTEM. The Central Information Display goes black intermittently due to resets of the Head Unit \(HU\-H3\). FaultB7F8F9 â“ âHU\-H: Resetâ will be stored in the HU\-H3.

JSON: [/v1/bulletins/11022110](/v1/bulletins/11022110)

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