2023-2024 Audi TFSI Engine Rough Idling TSB

Symptoms of Audi TFSI Engine Rough Idling

Owners of 2023-2024 Audi vehicles equipped with TFSI engines may notice that the "Engine does not run smoothly at idling speed after cold start." This condition is particularly noticeable when the engine is cold and can manifest as an uneven or unstable idle. Technicians may also find "Sporadic misfiring logged in event memory of engine control unit" during diagnostic checks.

These complaints tend to occur more frequently in vehicles primarily used for short drives. If you experience your Audi e-tron rough idling, especially under these conditions, it's advisable to have it inspected.

Technical Background

The root cause of the "Engine does not run smoothly at idling speed - all TFSI engines" issue is typically attributed to deposits accumulating in the inlet ports and on the inlet valves. TFSI (Turbocharged Fuel Stratified Injection) engines use direct fuel injection, meaning fuel is sprayed directly into the combustion chamber, bypassing the intake valves. Over time, oil vapors and exhaust gases (from the PCV system) can condense and bake onto the hot intake valves and ports, forming hard carbon deposits.

These carbon deposits restrict airflow, disrupt the air-fuel mixture, and can prevent the valves from sealing properly, leading to misfires and rough engine operation, particularly at idle speeds where precise airflow is critical.

Diagnosis and Trigger Conditions

When diagnosing an Audi e-tron rough idling complaint, technicians will typically check the engine control unit's event memory for any stored fault codes related to misfires. The presence of sporadic misfiring events, especially when combined with customer reports of rough idling after a cold start, points towards this specific issue.

The TSB also notes that vehicles used for frequent short drives are more prone to developing these carbon deposits. This is because the engine may not reach optimal operating temperatures long enough to burn off some of the accumulating deposits, exacerbating the problem over time.

Repair Procedure Summary

The recommended repair for the Audi e-tron rough idling condition involves cleaning the inlet valves and ports using a method called walnut blasting. This procedure is highly effective at removing stubborn carbon deposits without requiring extensive engine disassembly.

During the repair, the cylinder head does not need to be removed. Instead, technicians will remove only the intake manifold and/or compressor to gain access to the inlet ports and valves. A specialized granulate blasting unit is then used to blast crushed walnut shells at high pressure, which effectively scours away the carbon buildup. The repair must be performed according to detailed repair instructions provided by Audi.

Required Tools and Parts

To perform the walnut blasting procedure, specific tools and granulates are required:

• Granulate blasting unit: VAS 294 011
• Granulate: VAS 294 011/8 or 294 012 70 H00
• Diagnostic Tester: VAS 6160/VAS 6150, running the current version of ODIS (Windows 10)

These specialized tools ensure the cleaning process is performed effectively and safely, without damaging engine components.

Important Warranty Information

Owners should be aware that if their vehicle is outside of any applicable warranty, this Technical Service Bulletin is informational only. This means that the cost of diagnosis and repair for the Audi e-tron rough idling issue may not be covered by Audi. All warranty claims submitted for payment must adhere strictly to the Audi Warranty Policies and Procedures Manual, and claims are subject to review or audit by Audi Warranty.

TSB Revision History

This Technical Service Bulletin, Transaction Number 2075530/2, was initially published on October 8, 2024, as Revision 1. It was subsequently revised to Revision 2 on March 12, 2025, to include an updated header with an added PR code filter.

Source: NHTSA ID 11016532