⚠️ Audi manufacturer position
VW Group service manuals require tank emptying before removal; misfuel not warrantable.
Vehicle information
| Make | Audi |
|---|---|
| Model | A4 |
| Market status | Sold new in the US 1996–present (diesel limited years) |
| Body styles | Sedan, Wagon (Allroad) |
| Generations | B8, B9 (2017–2024), B10 (2025–present) |
| Engine options | Gasoline: 2.0L TFSI, 3.0L V6 (select trims) Diesel: 2.0L TDI and 3.0L TDI (limited US availability—mostly pre-2016) |
| Fuel tank capacity | 15.3–16.9 gal |
| Fuel system | FSI/gasoline DI; TDI common-rail |
| Access method | Under rear seat pump access typical — verify erWin |
| Anti-siphon | Yes |
| Service portal | Audi erWin / ELSA |
Misfuel risk High
Diesel A4 models remain on US roads with high gasoline misfuel risk.
If the engine was not started
Do not prime fuel system; tow for drain.
If the engine was started
Plan full fuel-system inspection on TDI; gasoline DI HPFP at risk if diesel burned.
Access procedure
- Disconnect battery ground strap; ignition OFF.
- Briefly open and close fuel door to relieve capless system pressure if equipped.
- Release fuel pressure per erWin/ELSA (relay or scan tool—avoid cranking with wrong fuel).
- Access fuel pump module (often under rear seat or cargo floor) per model erWin group.
- Drain tank using VW-approved fuel cart connected at module service ports.
- Replace fuel filter; inspect low-pressure and high-pressure components per contamination severity.
- Reinstall, reconnect battery, prime system, leak-check, and clear adaptations if required.
Related models
- A5
- S4
- Q5
Frequently asked questions
What should I do if I put the wrong fuel in my Audi A4?
Do not start the engine or cycle the ignition to RUN if the fuel pump may prime. Have the vehicle recovered to a USIFDA Certified Repair Facility and follow Audi service information for tank draining and fuel system inspection.
Does Audi warranty cover misfuel damage on an A4?
No. Audi warranties exclude damage from improper or contaminated fuel. Repairs are typically customer-pay; document the OEM-prescribed remediation procedure.
Can fuel be removed from an A4 through the filler neck?
Audi documents fuel recovery via the fuel pump module access and/or tank removal using approved equipment—not filler-neck siphoning. Follow ISTA/TIS or erWin procedures for your model year.
Need professional misfuel recovery?
Find a certified operator or read consumer guidance for your next steps.
Find an operator Consumer guidance