The Lemon Index
2020Complaints only. Too few sold to score: 16,263 in the U.S. in 2021 (sales source), under the 20,000 a fair per-car score needs. Owners filed 6 complaints in its first 3 years.
6 owner complaints, first 3 years 26–28 mpg combined, EPA
Similar cars, same year
2021 BMW 3 Series 172021 Acura TLX 1192021 Tesla Model 3 489
Lemon Index: 100 = the average car, lower is better.
Engines & versions
When problems show up
No complaints for this year listed a mileage, so we can't say when problems show up.
Questions to ask the seller
- Were recalls 22V742000 (back over prevention), 22V034000 (tires) and 21V606000 (seat belts) done? It has 4 recalls in all. Ask for the dealer printout, or check the VIN.
- Does it accelerate and hold speed smoothly, with no surging or stalling?
- Any clunks over bumps or uneven tire wear? Were struts, shocks or control arms replaced?
- Is the airbag light off, and were any airbag recalls done?
From this year's own recalls, top problems, top repair bills and Audi's repair notes. Recall repairs are free at any dealer.
How serious. Out of all 6 owner complaints filed so far (every year since it was sold, not just the first 3), owners reported:
“Average car” = what the same number of complaints would include at the rate across every model year we track. Owners report these themselves; NHTSA doesn't confirm the cause.
What owners complain about most. From owner complaints to the government.
Share of this year's owner complaints filed with NHTSA, not the share of cars that break. One complaint can name more than one area.
Check engine light on? Look up any code →
Fixes owners look up most.
From 199 YouTube videos · 63.6M views · 2017–2025 Audi A4
Prices people quote
- Price when new$49,90013 videos▶ Hear it
Most-watched topics
- Oil changes & service951K views
How To: Audi A4 B9 2017 Facelift MMI ResetAdvanced In-Car Technologies · 359K views · 5 videos - Infotainment, battery & electrical251K views
2017 - 2021 Audi A4 Remote Key Fob Battery Change - How To Remove & Replace A4 Key BatteriesPYR Automotive · 167K views · 2 videos - Brakes & ABS91K views
Audi A4 B9 Front Brakes Replacement Pads Rotors Allroad 2016 - 2025 DIYGibby's Garage · 91K views - Transmission & shifter79K views
Audi A4 DSG Transmission Service DIY (2017-2024 Audi B9 A4, A5, Sportback, Allroad)FCP Euro · 79K views
Before you buy, watch
Audi A4 saloon 2015-2019 review - CarbuyerCarbuyer · 1.0M views
Audi A4 saloon 2020 in-depth review - CarbuyerCarbuyer · 419K views
Should you buy a USED Audi A4 (B9)? - What goes WRONG?ReDriven · 294K viewsViews show how many people looked up each fix, not how often it breaks. Videos belong to their creators; we link to them. The 2021 is the same generation.
Costs are the middle (median) of the dollar amounts people say out loud in these videos, so one wild number can't swing it. They aren't verified bills or sales; real prices depend on year, miles, condition and where you live. Tap Hear it to jump to the moment.
Recalls 4
- Back over prevention · recall issued 2022
Due to a software issue, a blank or black screen may be displayed instead of the rearview camera image when the vehicle is placed in reverse gear.
- Tires · recall issued 2022
The rear axle alignment may not have been inspected after the repairs for Recall 21V-295 (42L1) were performed.
- Seat belts · recall issued 2021
The rear seat belt automatic locking retractors may deactivate early, which can prevent the child restraint system from securing properly.
Show all 4 recalls
- Suspension · recall issued 2021
The lock nut on the trailing arm of the rear axle may break due to stress corrosion.
Recall repairs are free at any dealer. A recall only matters if it's still open on that exact car, so check its VIN.
Canada? See recalls at Transport Canada
Crash test details
| Version | Overall | Front | Side | Rollover |
|---|---|---|---|---|
| Audi A4 4 DR AWD | ★★★★★ | ★★★★☆ | ★★★★★ | ★★★★★ |
| Audi A4 allroad SW AWD | not rated | not rated | ★★★★★ | not rated |
Fuel cost and engines
About $2,850–$3,050 (USD) a year in fuel (EPA estimate at U.S. prices, 15,000 miles or 24,000 km a year). Engines: 2.0L 4-cyl.
Every Audi A4 year. 2021 is highlighted. Lower is better.
Show 1 older years (2009–2009, YouTube reviews only, no complaint data)
Newest year first. Red = worse than average, gray = about average or too few complaints to score. #1, #2… = that year's YouTube rank among the 5 Audi A4 years with enough videos (#1 = the year owners and reviewers talk about most positively). It is not a reliability rank.
Embed this chart
Put this chart on your site, blog or forum. Free, with the credit line built in; the 2021 bar is highlighted.
<iframe src="https://lemonindex.com/embed/cars/audi-a4/?y=2021" title="Audi A4 reliability by model year (The Lemon Index)" width="100%" height="307" style="border:0;max-width:720px" loading="lazy"></iframe><p style="font-size:13px;margin:4px 0 0">Data: <a href="https://lemonindex.com/cars/audi-a4/2021/">Lemon Index</a> (2021 Audi A4 reliability)</p>Quick answers
Is the 2021 Audi A4 reliable?
We can't score it: only 16,263 were sold in the U.S. in 2021 (calendar-year sales), under the 20,000 we need for a fair per-car score. Owners filed 6 complaints with NHTSA in its first 3 years.
What are the most common 2021 Audi A4 problems?
In owner complaints to the government, the parts named most are speed control (33%), suspension (33%) and airbags (17%). That is the share of complaints, not the share of cars that break.
How many recalls does the 2021 Audi A4 have?
4 safety recalls (latest: back over prevention). Recall repairs are free at any dealer; check a specific car's VIN at nhtsa.gov/recalls.
What gas mileage does the 2021 Audi A4 get?
26 to 28 mpg combined, depending on the engine (EPA estimate).
Is the 2021 Audi A4 safe?
NHTSA gave it 5 out of 5 stars overall in its best tested version. Ratings differ by body style, and the full table is on the advanced page.
Does the 2021 Audi A4 have transmission problems?
Transmission and drivetrain issues aren't among its top 5 complaint areas.
How much does the 2021 Audi A4 cost in fuel a year?
About $2,850 to $3,050 a year, by the EPA's current estimate.
What engines does the 2021 Audi A4 have?
2.0L 4-cyl.
What Audi A4 year is better than the 2021?
Nearby, the 2019 drew fewer owner complaints per car sold (about a fifth as many complaints as the average car).
The Lemon Index counts owner complaints filed with the U.S. government (NHTSA) in a car's first 3 years, per car sold, against the average car of the same model years (100 = average, lower is better). It measures complaints, not crash safety. A complaint is an owner's report, not a confirmed defect. How it works