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Vehicle-specific service Transaction No.: 2081024/3
45 PSS Engine warning lamp (MIL) on - DTC U041800 Release date: Apr 29, 2026
Condition
Model(s) VIN Range Vehicle Specific Equipment
AS, S5 (FU), Q5, Q5
Sportback, SQ5, SQ5 2025
Sportback (GU) All Not applicable
REVISION HISTORY
revision [owe fouore
so | Revised Warranty (Add Warranty Table)
02/27/2026 | Revised Service (Updated Information)
02/12/2026 | Initial publication
Customer states:
The check engine light (MIL) is/was on.
Workshop findings:
The customer's description is plausible. After a period of CAN bus sleep, the warning light may no longer be
displayed, and it may not be possible to reproduce the complaint in the workshop.
The DTC "U041800 Brake electronics control unit implausible signal" with symptom code 487509 is stored in
diagnostic address 812C.
Technical Background
Signals from the ABS control unit are being provided with a delay, triggering the warning message.
Production Solution
This bulletin will be updated when more information is available. A solution is currently under development.
Service
1. Diagnose the vehicle according to the instructions listed below. If the customer's vehicle condition matches the
condition listed in the Technical Background of this PSS TSB, explain to the customer that a solution is
expected to be available by the end of the 2" quarter of 2026 (subject to change) and that no repairs are
necessary at this point.
2. Donot replace any components for this condition since this will not resolve the customer's concern.

3. Create a PSS record in the PSS application through the Pending Service Solutions (PSS) link in Audi Now;
Service | AU-US > Pending Service Solutions (PSS).
This PSS aims to provide support during the repair. Please delete DTC U041800 as specified above (postpone
other repairs). The original customer complaint may have been resolved by a bus sleep cycle.
Please check the vehicle's 12V power supply is working correctly and delete the DTC above and ensure there are
not any no-load current draw sources (e.g. PSS 2081155). Please re-evaluate the vehicle based on the clear
complaints and other entries in all control units and perform the required repairs.
Measures to ensure the ABS control unit signals are provided correctly and to revise the warning message concept
are being developed and are expected to be made available in the second quarter of 2026.
Note: The target date communicated here is based on planning and is not binding. During the validation, technical
and regulatory approval of measures, there may be delays or hindrances in providing the measure throughout the
entire process. This must be considered accordingly when communicating with customers.
Warranty
Claim Type: + Ifthe vehicle is outside of any warranty, this Technical Service Bulletin is
informational only.
Damage Code: 0039
Labor Operations: GFF / Guided Functions 0150 0010 See SRT with
associated operations
GFF / Guided Functions 0150 0060 Time stated on the
diagnostic protocol
Claim Comment: As per TSB 2081024/3
All warranty claims submitted for payment must be in accordance with the Audi Warranty Policies and Procedures
Manual.
Please note the information on predecessors and items that are included and excluded in the repair operations, as
well as any associated tasks.
Claims are subject to review or audit by Audi Warranty.
Try to reproduce the customer complaint (based on the description/cause of the issue), so that it can be clearly
assigned to this TSB. The following repair must only be carried out if all the criteria (model/type, chassis number,
engine/motor, gearbox code, PR number(s), part number, software version, code, etc.) apply exactly. Otherwise, this
solution will not eliminate the problem and repeat repairs may be necessary. In such a case, the warranty claim may
be rejected, and the cost of the parts may be charged back.
Additional Information
All part and service references provided in this TSB (2081024) are subject to change and/or removal. Always check
with your Parts Department and/or ETKA for the latest information and parts bulletins. Please check the Repair
Manual for fasteners, bolts, nuts, and screws that require replacement during the repair.
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