2025 BMW X1/X2 FC 034AEF Exhaust Cold Start Not Controllable

BMW has released Service Information Bulletin (SIB) 12 03 24, Revision 3, dated December 17, 2025, to address an issue affecting certain 2025 BMW X1 (U11) and X2 (U10) Sports Activity Vehicles equipped with B48P and B48R engines. This bulletin supersedes the previous SIB 12 03 24 dated December 2025.

The SIB addresses instances where the "Engine Malfunction Warning" is illuminated and the fault code FC 034AEF, labeled "Exhaust Cold Start, Not Controllable", is stored in the Digital Motor Electronics (DME) system. This condition is primarily caused by a DME calibration error.

Symptoms

Owners of affected 2025 BMW X1 or X2 vehicles may observe the following symptom:

• The "Engine Malfunction Warning" light is illuminated on the instrument cluster.

Fault Codes / DTCs

The primary diagnostic trouble code associated with this issue is:

Code	Description	Module
FC 034AEF	Exhaust Cold Start, Not Controllable	DME

Important Warnings

For specific programming procedures, particularly the IRAP (Integration and Repair Programming) process, BMW has issued critical instructions:

• "Important notes: We must have engine oil and coolant at the same temperature (within 1 degree is permitted) prior to starting the IRAP. If the vehicle has been sitting either outside or inside and can be programmed without the engine being started, you can proceed."
• "If the vehicle has a warm and/or hot engine we CANNOT proceed. Warm and/or hot engines will require 8+ hours sitting. Once the engine has cooled down and the temps are within 1 degree of each other please set up for IRAP."

Repair Procedure Summary

The repair for the 2025 BMW X1 FC 034AEF exhaust cold start issue involves updating the vehicle's software. The initial step requires programming the vehicle using ISTA 4.46.2X or a newer version (released March 11, 2024), targeting an Integration level of U006-24-03-5XX or higher. ISTA will automatically reprogram and code all programmable control modules lacking the latest software.

If the fault code FC 034AEF reappears, or if the vehicle's i-level is already above U006-24-03-5XX, technicians must further investigate the DME software identifier (SWFK). If the SWFK matches specific versions (9B85, A9D7, AC0A, AC09), a TSARA programming case titled "IRAP B4x VANOS" must be created. This IRAP process requires strict adherence to engine temperature conditions.

After completing the IRAP, the vehicle must be connected to ISTA to calculate a new measures plan, and the DME will be automatically selected for programming. Following this, a cold start of the vehicle is required. If the fault code returns after the warm-up phase, another TSARA case must be created. If the SWFK does not match the specified versions, the vehicle software should be updated to U006-25-11-5xx or higher, released with ISTA version 4.57.1x on December 3, 2025.

Required Tools or Parts

During any programming procedure, it is crucial to connect a BMW-approved battery charger/power supply. This ensures stable voltage throughout the process, preventing potential issues.

Owner Action

If your 2025 BMW X1 or X2 displays an "Engine Malfunction Warning" or you suspect an issue related to the 2025 BMW X1 FC 034AEF exhaust cold start condition, it is recommended to contact your authorized BMW dealer. They have the necessary diagnostic tools and software to perform the required updates and repairs under SIB 12 03 24. This repair is covered under the terms of the BMW New Vehicle Limited Warranty or the BMW Certified Pre-Owned Program, if applicable.

NHTSA ID: 11026948