Condition

Customer statement:

The customer complains that the auxiliary heating cannot be activated in the vehicle. The message“Auxiliary heating function not available”is displayed on the MMI and the auxiliary heating icon is greyed out in the vehicle.

The customer complains that the interior heating output is insufficient after a cold start of the vehicle at ambient temperatures below 10 °C and without using auxiliary heating mode in advance. After the vehicle has warmed up, the heating output in the vehicle interior is not limited in any way.

Workshop findings:

The workshop can reproduce the complaint in the vehicle. The event memory entryB176829: Flame monitor: implausible signal, active/static or passive/intermittentis logged in diagnostic address 0018.

Postpone repair

Technical Background

Software issue.

Production Solution

In week 9/2025 (Audi A5) or week 12/2025 (Audi Q5) with software version 0240.

Service

Please postpone the repair as there is currently no effective repair for the complaint described by the customer. There is no hardware issue on the auxiliary heating.

Unlock the heater unit in the affected vehicles via the diagnostic tester. This restores the auxiliary heating function.

A solution is not to be expected before the fourth quarter of 2025.

If DISS is used in your market.

As part of the process, it is necessary that you activate the e-mail notification function in DISS for this TPI/this complaint. You will then automatically receive an e-mail from the DISS system as soon as new information for this complaint is available.

Proceed as follows:Copy the TPI into the complaint in DISS. When you do so, you will see a message indicating that a measure is being developed for the selected TPI and that you can receive an e-mail notification when the solution is available. If you would like to receive a notification, please select “Yes” for the query regarding the e-mail notification. Please note that you can only receive an e-mail notification if you have provided your e-mail address in the dealer portal.

Please do not close this complaint. If no measure is available before the archive date in 12 months, please extend the archive date. To do this, open the complaint in the DISS Monitor (order list → Open archive candidates tab) and change the archive date to the maximum period using the calendar icon.

Warranty

Replacing parts or attempting repairs will not fix the problem. Unjustified work/replacement parts will be charged back. Invoicing under warranty is not permitted.

Additional Information

A solution is not to be expected before the fourth quarter of 2025.

All parts and service references provided in this TPI are subject to change and/or removal.

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