2021 Audi A6 Engine Noise and DTC P2BA300 TSB

Symptoms of Engine Noise and Belt Issues

Owners of affected 2021 Audi A6, A4, A5, and Q5 models may experience specific symptoms related to the starter/generator drive belt. The most common sign is a grinding, squeaking, or tweeting noise emanating from the engine compartment. This noise typically originates from the poly V-belt, also known as the alternator belt.

In more severe cases, if the poly V-belt has fallen off or is significantly damaged, the driver information system (DIS) may display a warning message: "Electrical system: Malfunction! Please go to workshop". This indicates a critical issue with the vehicle's electrical system due to the belt failure.

Fault Codes / DTCs

When these symptoms occur, the engine control module (ECM), identified as J623 (address word 0001), may store a specific Diagnostic Trouble Code (DTC). The relevant fault code for this issue is:

Code	Description	Module
P2BA300	Starter/Generator mechanical performance	ECM

This DTC, Audi A6 P2BA300, directly points to a mechanical performance problem with the starter/generator system, often linked to the drive belt.

Diagnosis and Trigger Conditions

Diagnosing the source of the noise or poly V-belt issue involves a few steps. Technicians will first listen for grinding, squeaking, or tweeting noises from the engine compartment while the engine idles. An example of the noise is available via a QR code provided in the TSB.

To confirm if the poly V-belt is the source of the noise, a small amount of tap water can be sprayed onto the inside of the belt. If the noise disappears after spraying, it confirms the poly V-belt and belt tensioner are the culprits. The technical background for this issue points to a deviation on the rollers of the belt tensioner.

Repair Procedure Summary

Audi Technical Service Bulletin 2061461/5 outlines the repair process for addressing the Audi A6 P2BA300 issue. The procedure varies slightly depending on whether the primary symptom is noise or a damaged/missing belt.

For Grinding, Squeaking, or Tweeting Noises

1. Assess Noise: Run the engine at idle speed to confirm and assess the noise.
2. Confirm Source: Spray the inside of the poly V-belt with a small amount of tap water. If the noise stops, the belt system is the source.
3. Component Replacement: Replace the poly V-belt and the belt tensioner. It is important to note: if a new belt tensioner has already been installed, it should not be replaced again.

For Damaged or Fallen Off Poly V-Belt

1. Component Replacement: Replace both the belt tensioner and the poly V-belt. Similar to the noise scenario, if a new belt tensioner has been recently installed, it should not be replaced again.

Post-Repair Check

After replacing the components, technicians must check for correct belt running alignment. The engine should be run at idle speed, and 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) in relation to the tensioning roller (B).

Required Parts

The following parts are typically required for this repair. Technicians should always consult ETKA (Electronic Parts Catalog) and their Parts Department for the latest information and part numbers:

• Fasteners, Bolts, Nuts, and Screws: As needed per the repair manual.
• Belt Tensioner: Quantity 01.
• Poly-V Belt: Quantity 01.

Warranty Information

This service is covered under Audi's warranty for vehicles up to 48 months or 50,000 miles. For Audi Certified Pre-Owned (CPO) vehicles, the claim type is G10, requiring owner verification. If the vehicle is outside of warranty, this Technical Service Bulletin is for informational purposes only, and the repair cost would be the owner's responsibility.

The service number associated with this repair is 1373. Specific damage codes are used for warranty claims:

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

Labor operations include specific time units for tasks such as ribbed belt removal and installation (1372 1915), belt tension damper removal and installation (1373 1965), checking poly V-belt run alignment (1372 0199), and diagnostic work for checking and clearing fault codes (0150 0000).

This TSB, identified as 2061461/5, supersedes Technical Service Bulletin Group 13 number 21-15, dated July 14, 2021.

---

Source: NHTSA ID: 10225529