# Service bulletin B121125

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: 11025668
- Published by NHTSA: 2025\-11\-25
- Manufacturer's number: B121125
- Manufacturer's date: 2025\-11\-12
- NHTSA component: ENGINE; ELECTRICAL SYSTEM

## NHTSA's summary

One or both of the following faults stored in the DME: 034AA5 \- Mixture control bank 1, lambda regulation, mixture too lean 034AA8 \- Mixture control bank 1, lambda adaptation, mixture too rich And additionally with the faults above, these affected vehicles may have one or more of the followingirregular combustion\-related faults also stored: 033812 033813 033814 033815 033816 033817 033818 033819

## The document

- [NHTSA's copy of the document (PDF)](https://static.nhtsa.gov/odi/tsbs/2025/MC-11025668-0001.pdf)
- [If that address does not open, try this one](https://static.nhtsa.gov/odi/tsbs/2025/MC-11025668-9999.pdf)

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

## Components

Electrical system, Engine

## Vehicles listed

- 2024 to 2025 BMW 530I
- 2024 to 2025 BMW 740I

## Recalls for the same vehicles and component

- [26V056000](/recalls/nhtsa/26V056000.md), 2026-01-30: ELECTRICAL SYSTEM:STARTER ASSEMBLY
- [25V202000](/recalls/nhtsa/25V202000.md), 2025-04-01: ELECTRICAL SYSTEM:STARTER ASSEMBLY; ELECTRICAL SYSTEM:ALTERNATOR/GENERATOR/REGULATOR
- [23V700000](/recalls/nhtsa/23V700000.md), 2023-10-18: ELECTRICAL SYSTEM:ADAS:DRIVER MONITORING:CAMERA/SENSOR

## Other bulletins for the same vehicles and component

- [B630526](/bulletins/11037532.md), 2026-09-28, Service bulletin: ELECTRICAL SYSTEM. After programming the vehicle via ISTA/RSUto I\-level …26\-03\-5xx, customer may reportsome of the interior ambient lighting strips\(arrows\) may begin to fail sporadically after adeep sleep cycle. This concern is temporary and the interiorambient lighting will be restored on its ownafter the vehicle is locked/unlocked or colorselection setting is changed.
- [B121126](/bulletins/11037505.md), 2026-09-28, Service bulletin: ENGINE. Potential customer complaints with no fault codes stored / No MIL displayed. 1. “Rough idle after idling for a longer period of time” 2. “Vehicle feels like it is misfiring at idle” The automatic Start/Stop function is deactivated. The vehicle is stopped and the engine runs at idle speed. After prolonged idle operation \(approximately 30 to 50 seconds\), a slight jolt or slight change in idlespeed may be noticeable. There are no relevant errors in the DME fault code memory. No mixture control error, no misfiring, no error relating to a relevant component of the drive system. Motor vehicles affected: 1. Only MHEVs \(mild hybrid electric vehicle\) with crankshaft\-driven starter generator. 2. Only vehicles with optional equipment 01CE = recuperation system 3. Affected I\-levels: I\-level 24\-07\-500 or higher
- [B611526](/bulletins/11036455.md), 2026-08-28, Service campaign: ELECTRICAL SYSTEM. In vehicles equipped with the Roof Function Center “FZD‑21” variant, a quiescent‑current violation mayoccur if the system fails to enter sleep mode. When this sleep error is present, a remote software upgrade\(RSU\) may be aborted and the FZD can become degraded. The following Check Control Messages \(CCMs\) may be displayed: “Energy Management — Increased Energy Consumption While Parked.” “Software Upgrade Failed — Workshop Visit Required.”
- [B630526](/bulletins/11036381.md), 2026-08-27, Service bulletin: ELECTRICAL SYSTEM. After programming the vehicle via ISTA/RSUto I\-level …26\-03\-5xx, some of the interiorambient lighting strips \(arrows\) may begin tofail sporadically after a deep sleep cycle.
- [B340124](/bulletins/11036380.md), 2026-08-27, Service campaign: ELECTRICAL SYSTEM. After replacement of the Integrated Braking system \(IB\)/Power Brake the total distance covered might belower than when handed over to the workshop for the repair.
- [B110326](/bulletins/11036376.md), 2026-08-26, Service bulletin: ENGINE. This Service Bulletin provides instructions to clean the intake valves using the BMW Carbon Blaster Tool P/N 81 29 2 208 034 and the S68T / XB1T Kit P/N 83 30 5 BAD 3D5. Refer to SI B04 12 11 for existing documentation about the carbon blaster tool and SI B04 02 26 for the S68T /XB1T tool kit.
- [B063926](/bulletins/11035476.md), 2026-08-03, Other: ENGINE. Starter Generator Return
- [B652026](/bulletins/11035404.md), 2026-07-31, Service bulletin: ELECTRICAL SYSTEM. The Central Information Display \(CID\) side of the Multifunction Display \(MFD\) may flicker intermittently. Theflickering manifests itself in three phases: The image is distorted The central information display turns black \(black screen\) The image is OK again The complete flickering episode with all the above\-mentioned three phases only lasts about half a second intotal each time.
- [B170126](/bulletins/11035398.md), 2026-07-31, Service campaign: ENGINE. The coolant vent lines of the low\-temperature circuit are designed to remove air bubbles from the system toensure optimal cooling performance. Internal quality inspections have revealed that leaks may occur due tolocalized material aging on the vent lines. These leaks occur because the material originally used is notsufficiently resistant to the continuously high temperatures. A coolant leak may result and cause a yellow check control message and reduced engine performance.
- [B120326](/bulletins/11035396.md), 2026-07-31, Emissions: ENGINE. Due to an implementation error in various OBD diagnostics in the vehicle's control units, in very rare cases itmay happen that stored fault memory codes \(DTCs\) and the MIL \(warning light\) are not automaticallydeleted even though the underlying malfunction has already been rectified. This does not comply with the statutory OBD specifications.

JSON: [/v1/bulletins/11025668](/v1/bulletins/11025668)

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