2021-2025 Audi A4, A6, Q5 Drive Belt Noise TSB 2061461/15

Owners of 2021-2025 Audi A4, A6, and Q5 models equipped with the 2.0 ltr. Inline 4-cyl. TFSI engine may experience unusual noises from the engine compartment or a specific warning message on their driver information system. This issue, detailed in Audi Technical Service Bulletin (TSB) 2061461/15, points to problems with the starter/generator drive belt, also known as the poly V-belt, and its tensioner.

This TSB, released on November 19, 2025, provides diagnostic and repair procedures for technicians to address these concerns. It is an update to previous revisions, with Revision 15 incorporating revised service instructions, Revision 14 (dated September 26, 2025) updating the header, model year information, and warranty details, and Revision 13 (dated June 27, 2025) also revising header and model year information.

Symptoms Owners May Notice

Owners typically report one or both of the following issues:

• A grinding, squeaking, or tweeting noise emanating from the engine compartment.
• A message displayed in the driver information system (DIS) that reads: "Electrical system: Malfunction! Please go to workshop". This warning specifically appears if the poly V-belt has fallen off.

Upon inspection, technicians often find that the grinding, squeaking, or tweeting noise originates from the poly V-belt (alternator belt). In more severe cases, the poly V-belt may be damaged or have completely fallen off the wheel roller.

Important Warnings for Owners and Technicians

Audi has issued specific advisories within TSB 2061461/15 to ensure correct diagnosis and repair, and to prevent unnecessary part replacements or charges:

• Do not replace already new components: "If a new belt tensioner has already been installed (in the workshop or after the production change), do not replace it again." This applies to both scenarios where noise is present or the belt has fallen off.
• Starter-generator replacement is not the solution: "Replacing the belt-driven starter-generator will not fix the problem." This clarifies that the issue lies with the belt and tensioner, not the starter-generator unit itself.
• Careful handling of parts: "Please ensure that the belt tensioner (including the retaining tab) is not damaged during removal. Damage to the component would make analyzing the parts impossible. In such cases, we may charge back the damaged parts." This emphasizes the importance of careful removal during the repair process.

Technical Background of the Issue

The root cause of the Audi A6 drive belt noise and related issues is identified as a deviation on the rollers of the belt tensioner. This deviation can lead to improper belt alignment, excessive wear, noise, or even the belt detaching entirely.

Audi implemented production changes to address this. For A4/A5 models, the belt tensioner was updated around July 23, 2021, and the poly V-belt around January 16, 2024. For A6/A7 models, the belt tensioner was updated around July 22, 2021, and the poly V-belt around March 24, 2025. For Q5 models, the belt tensioner was updated around September 23, 2021, and the poly V-belt around April 30, 2024. These dates are crucial for determining if a vehicle was manufactured before or after the production change.

Diagnosis Procedure

Technicians follow a specific diagnostic process to confirm the source of the noise or the cause of the belt detachment:

• Noise Assessment: The engine is run at idle speed to assess the grinding, squeaking, or tweeting noise. An example of the noise can be heard in a supporting video accessible via a QR code (Figure 1 in the TSB).
• Water Spray Test: To confirm the noise source, a small amount of tap water is sprayed onto the inside of the poly V-belt using a spray bottle. If the noise disappears after this application, it confirms the poly V-belt and belt tensioner as the source of the problem. This test helps differentiate the poly V-belt noise from other potential engine noises.

Repair Procedure Summary

The repair procedure outlined in TSB 2061461/15 depends on the specific scenario:

Scenario 1: Grinding, Squeaking, or Tweeting Noises

If the water spray test confirms the poly V-belt as the source of the noise, the poly V-belt and the belt tensioner must be replaced. It is important to note that if a new belt tensioner has already been installed (either in the workshop or during a production change), it should not be replaced again. The TSB explicitly states that replacing the belt-driven starter-generator will not resolve this issue.

Scenario 2: Poly V-belt Damaged or Fallen Off

If the poly V-belt is damaged or has fallen off, and the vehicle was manufactured before the aforementioned production changes, both the belt tensioner and the poly V-belt must be replaced. Similar to Scenario 1, if a new belt tensioner has already been installed, it should not be replaced again.

Post-Repair Check

After replacing the components, technicians must check the belt running alignment. With the engine running at idle speed, the belt must not protrude forward or backward over the roller edge of the tensioner. Figure 2 in the TSB illustrates the correct alignment, showing the poly V-belt (A), the tensioning roller of the belt tensioner (B), and the belt tensioner (C). Figure 3 provides examples of damaged parts, such as a bent holding arm on the tensioner.

Warranty Information

Repairs performed under TSB 2061461/15 are subject to Audi's Warranty Policies and Procedures Manual. The Service Number associated with this bulletin is 1373. Technicians will use specific Damage Codes and Labor Operations for warranty claims:

• Damage Code 0020: For a noisy belt.
• Damage Code 0015: For a belt that has come off.

Labor Operations include:

• Ribbed belt remove + install (Operation Code 1372 19XX)
• Belt tension damper remove + install (Operation Code 1373 19XX)
• Check Poly V-Belt run alignment (Operation Code 1372 0199, with an estimated time unit of 10 TU)

For vehicles outside of warranty, this Technical Service Bulletin serves as informational guidance only. All part and service references provided in this TSB are subject to change or removal by Audi.

NHTSA ID: 11026211