2023-2024 Audi Engine Start System Warning TSB

Symptoms

Owners of affected 2023-2024 Audi vehicles may observe specific warning messages appearing in the instrument cluster. These messages include:

• "Engine start system: fault"
• "Power unit start system: fault"

Despite these warnings, the vehicle typically exhibits no functional issues related to the engine start or power unit systems.

Fault Codes / DTCs

When the "Audi engine start fault" messages appear, a specific Diagnostic Trouble Code (DTC) is stored in the Comfort Control Module, also known as -J393- (address word 0046). This TSB identifies the following code:

Technical Background

Audi has identified that the root cause of the "Audi engine start fault" and related warning messages is a software issue within the Comfort Control Module -J393-. This module, located at address word 0046, is responsible for various comfort and control functions, and a glitch in its software can lead to the erroneous fault detection and display of warning messages.

Repair Procedure Summary

To resolve the "Audi engine start fault" and clear DTC B200047, a software update for the Comfort Control Module -J393- is required. This procedure is performed using the Software Version Management (SVM) system, following the instructions detailed in TSB 2011732: 00 Software Version Management (SVM), operating instructions.

Technicians will update the Comfort Control Module -J393- using the SVM action code 46A034. The update involves flashing the module with new software versions. For models like the A4, A5, Q7, Q8, and Q8 e-tron, the old software part number 8W1.907.064.* (version 0627) will be updated to the new software part number 8W1.907.064.* (version 0628 or higher). For the e-tron GT, the old software part number 992.907.064.* (version 0627) will be updated to the new software part number 992.907.064.* (version 0628 or higher).

Important Warnings

During the software update process, it is crucial that the key must be on the emergency reader coil. Failure to follow this instruction could disrupt the update and potentially cause further issues with the control module.

Owner Action

If your 2023-2024 Audi is displaying an "Engine start system: fault" or "Power unit start system: fault" message, or if you suspect your vehicle is affected by the Audi engine start fault, you should schedule an appointment with an authorized Audi dealership. The dealership will perform the necessary software update to the Comfort Control Module -J393- as outlined in TSB 2071735/4.

This repair is typically covered under Audi's warranty for up to 48 months or 50,000 miles, whichever comes first, under claim type 110. It is advisable to confirm warranty coverage with your dealer prior to service.

Source: NHTSA ID: 10253755