2025-2026 BMW 2 Series / X3 Ambient Lighting Malfunction TSB

BMW has issued Service Information Bulletin (SIB) 63 09 25 (Revision 1) to address an ambient lighting malfunction affecting certain 2025-2026 BMW 2 Series Gran Coupe (F74) and X3 Sports Activity Vehicle (G45) models. This bulletin, which supersedes the previous SI B63 09 25 dated September 2025, provides a completely revised procedure and updated claim information for this issue.

Owners may notice that some interior ambient lighting strips no longer function correctly after their vehicle has undergone programming via ISTA/RSU to software version 25-07-5xx. This can lead to a noticeable reduction in interior illumination and comfort.

Symptoms

The primary symptom of this issue is the improper functioning of interior ambient lighting strips. This typically occurs after a vehicle software update. Owners might observe that specific lighting elements within the cabin are either dim, flickering, or completely inoperative.

Fault Codes / DTCs

When diagnosing this BMW 2 Series X3 ambient lighting malfunction, technicians may find several fault codes stored in the vehicle's system. These codes indicate an issue with the interior lighting layering and incorrect versioning of specific LIN slaves.

For F74 (2 Series Gran Coupe) models, possible fault codes include:

• 804A38: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 5"
• 804A39: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 6"
• 804A3E: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 11"

For G45 (X3 Sports Activity Vehicle) models, possible fault codes include:

• 804A34: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 1"
• 804A35: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 2"
• 804A36: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 3"
• 804A37: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 4"
• 804A38: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 5"
• 804A3A: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 7"
• 804A47: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 8"
• 804A48: "Interior lights layering (IL-LIN_3): versioning incorrect: LIN slave 9"

It's important to note that these fault codes may or may not be present, but the ambient lighting issue can still occur.

Cause

The root cause of this BMW 2 Series X3 ambient lighting malfunction is identified as unfavorable logic within the LED control unit hub. This logic issue manifests after the vehicle's software is updated to version 25-07-5xx via ISTA/RSU programming.

Repair Procedure Summary

The correction for this issue involves following a specific test plan to properly encode the LED control unit hub. The bulletin outlines two primary methods for diagnosis and repair: Remote Diagnosis with RITA and ISTA Diagnosis.

Using Remote Diagnosis with RITA

1. A technician will first verify the customer's concern to confirm the ambient lighting is not functioning as expected.
2. The vehicle is connected to the RITA system to perform a remote diagnostic test.
3. Fault codes are read from the vehicle's system.
4. The technician performs the NAD Encoding service function (ABL-DIT-AS6300_NAD_CODIEREN) for the LIN node "slave module" addresses.
5. All faults are cleared, the vehicle is allowed to enter a sleep cycle, and the operation of the interior ambient lighting is checked.

Using ISTA Diagnosis

1. The technician verifies the customer's concern. If ambient lighting is low, a piece of cardboard can be used to cover the area for better visibility of the lighting strips.
2. An approved BMW battery charger or power supply is connected to the vehicle (referencing SI B04 23 10 for battery charger guidelines).
3. Fault codes are read from the vehicle.
4. A BCP Control unit reset is performed.
5. The Nad Encoding Service Function (ABL-DIT-AS6300_NAD_CODIEREN) is performed using ISTA 4.57.2x or higher. This function can be found under "Vehicle Management > Service Functions > Body > Lighting > Encode NAD."
6. All faults are cleared, the vehicle is allowed to enter a sleep cycle, and the operation of the interior ambient lighting is checked.

Important Information for Owners

No parts are required to resolve this ambient lighting issue. The repair involves a software encoding procedure. This service is covered under the terms of the BMW New Vehicle Limited Warranty for Passenger Cars and Light Trucks. The repair code associated with this fix is 6331251500, described as "Light module/LED module, multicoloured interior ambient lighting Permanent malfunction."

Owner Action

If you own a 2025-2026 BMW 2 Series Gran Coupe (F74) or X3 Sports Activity Vehicle (G45) and are experiencing an ambient lighting malfunction after a software update, or if you have any of the listed fault codes, you should contact your authorized BMW dealer. They will be able to perform the necessary diagnostic and encoding procedures outlined in SIB 63 09 25 to restore your ambient lighting functionality.

NHTSA ID: 11026955