2021 Audi A4 Reliability Report
NHTSA data as of Oct 15, 2026Published Oct 19, 2026
Ranks 5th of 24 A4 years we score.
- Owner complaints
- 14
- 2 are recall notices
- Per 10,000 cars
- 6.6
- 18,268 made for the U.S.
- Vs the average car
- 0.45×
- same age, 1× is average
- Serious outcomes
- 5
- crash, fire, injury, stall or tow
- Recalls
- 4
- NHTSA crash rating
- 5★
- overall, out of 5
Should You Buy the 2021 Audi A4?
Yes. Our reliability score for the 2021 Audi A4 is 80 out of 100, which rates Excellent. Owners reported about half as many problems as for the average car of the same age. It ranks 5th of the 24 A4 years we score.
The most reported problem is the instrument cluster, mostly stopped working (4 of 14 complaints). Owners also complain about unintended acceleration. 5 of the 14 complaints describe a serious outcome, such as a crash, a fire, an injury or stalling while driving.
It has 4 recalls. Audi also offers three warranty extensions that may still apply, for problems with the air conditioning, fuel system and driver assistance systems. NHTSA rates it 5 out of 5 stars overall in crash tests. For comparison, the 2020 scores 62 and the 2022 scores 75.
Before you buy, check that the recalls were done, ask an Audi dealer about warranty extension AWA-21-01 and get an independent inspection. The full checklist is at the end of this page.
Pros
- Excellent reliability score of 80
- About half the problems of the average car its age
- Recent complaints at or below average
- No do-not-drive or park-outside recalls
Cons
- Instrument cluster: stopped working4 complaints
- Unintended acceleration (cause not stated)2 complaints
How the 2021 A4 Earned Its Score
Every model year starts at 100. Each part takes points away when this year has more problems than the average car of the same age. How we score
| Item | Vs average | Points lost |
|---|---|---|
| Starting score | 100 | |
| Serious problems | 0.45× | −7 |
| Everyday problems | 0.45× | −3 |
| Problems in the last two years | 0.33× | −4 |
| Recalls | 1.0× | −6 |
| Score | 80 |
What Owners Report
We read all 14 complaints filed with NHTSA for the 2021 Audi A4, one by one, and grouped them by the problem they describe. The most reported problems come first.
Instrument cluster: stopped working
4 complaints (29%)
A feature that stopped working, problems that come and go and a failure.
Unintended acceleration (cause not stated)
2 complaints (14%)
Sudden acceleration. Both describe a serious outcome, most often a crash.
Reported Once (7)
Show the 7 problems reported once
- AWD or rear differential: vibration or shudder
- Airbags: no deployment in a crash
- Automatic emergency braking: hard braking with nothing ahead
- Loss of power (cause not stated)
- Rearview camera: works on and off
- Tires: damage
- Vibration (cause not stated)
How the 2021 Audi A4 Compares With Other Years
The other A4 years of the 5th generation (B9), 2017 to 2025, and the years just before and after it.
| Year | Rating | Score | Vs average | Per 10k cars | Recalls | Most reported problem |
|---|---|---|---|---|---|---|
| 2025 | Not scored | – | – | 9.8 | 0 | – |
| 2024 | Not scored | – | – | 7.0 | 0 | Tires: damage |
| 2023 | Good | 78 | 0.56× | 5.9 | 1 | Stall (cause not stated) |
| 2022 | Good | 75 | 0.55× | 7.5 | 3 | – |
| 2021 This year | Excellent | 80 | 0.45× | 6.6 | 4 | Instrument cluster: stopped working |
| 2020 | Caution | 62 | 4.4× | 146.6 | 4 | Screen and audio: works on and off |
| 2019 | Excellent | 87 | 0.25× | 4.5 | 1 | Automatic emergency braking: hard braking with nothing ahead |
| 2018 | Excellent | 80 | 0.44× | 12.1 | 4 | Automatic emergency braking: hard braking with nothing ahead |
| 2017 | Excellent | 85 | 0.39× | 13.7 | 6 | Cooling system: a leak |
| 2016 | Excellent | 86 | 0.38× | 11.2 | 3 | Steering: locking up |
2021 Audi A4 Recalls
Four recalls cover the 2021 Audi A4. The most recent was issued in October 2022: “Rearview Display Inoperative/FMVSS 111.” A VIN check at NHTSA shows which are still open on a given car.
Rearview Display Inoperative/FMVSS 111
A blank rearview camera display can reduce the driver's rear visibility, increasing the risk of a crash.
NHTSA 22V742000Recall report (PDF)Owner letter (PDF)Issued Oct 5, 2022. By the third quarter of 2024, 93% of the cars in this recall had been fixed.
Rear Axle May Be Misaligned
Rear axle misalignment may cause premature or uneven tire wear, increasing the risk of a crash.
NHTSA 22V034000Recall report (PDF)Owner letter (PDF)Issued Jan 26, 2022. By the fourth quarter of 2023, 97% of the cars in this recall had been fixed.
Seat Belt Locking Retractor Malfunction/FMVSS 208
The rear seat belt automatic locking retractors may deactivate early, which can prevent the child restraint system from securing properly. An unsecured child restraint system can increase the risk of injury during a crash.
NHTSA 21V606000Recall report (PDF)Owner letter (PDF)Issued Aug 5, 2021. By the second quarter of 2023, 96% of the cars in this recall had been fixed.
Rear Axle Lock Nuts May Break
A broken lock nut may misalign the rear axle, causing a loss of control and increasing the risk of a crash.
NHTSA 21V295000Recall report (PDF)Owner letter (PDF)Issued Apr 26, 2021. By the first quarter of 2023, 96% of the cars in this recall had been fixed.
2021 Audi A4 Warranty Extensions and Programs
Audi has three warranty extensions for the 2021 Audi A4, separate from its recalls. They are for problems with the air conditioning, fuel system and driver assistance systems. Whether one applies to a car depends on its VIN, which an Audi dealer can check.
- Warranty extensionAudi AWA-21-01
Air conditioning evaporator failure
- The problem:
- The air conditioning evaporator can fail. The bulletin does not describe the symptoms.
- The fix:
- An Audi dealer repairs or replaces a failed A/C evaporator, with any parts and labor needed.
- Who qualifies:
- Certain A4, S4 and Q7 from model year 2017 and A5, S5 and Q5 from 2018. The bulletin gives no last model year. Cars already repaired still qualify, but totaled cars do not.
- Coverage:
- 10 years or 100,000 miles from the original in-service date, whichever comes first.
- Warranty extensionAudi AWA-22-05
Faulty electric fuel pump
- The problem:
- The electric fuel pump can be faulty. The bulletin does not describe the symptoms.
- The fix:
- An Audi dealer repairs or replaces a faulty electric fuel pump, with any parts and labor needed.
- Who qualifies:
- Certain 2018 to 2021 S4, S5 and SQ5, 2019 to 2021 Q8 and A8, and 2020 and 2021 Q7. Cars already repaired still qualify, but totaled cars do not.
- Coverage:
- 15 years or 150,000 miles from the original in-service date, whichever comes first.
- Warranty extensionAudi AWA-24-04
Automatic emergency braking system faults
- The problem:
- The automatic emergency braking, or AEB, system can malfunction when its control unit, a camera, the LIDAR or a sensor fails.
- The fix:
- An Audi dealer repairs the AEB fault and Audi pays 75 percent of the cost. Damage from crashes, impacts, moved sensors or weather is not covered.
- Who qualifies:
- Certain Audis covered by the settlement, with a confirmed fault in the AEB control unit, cameras, LIDAR or sensors. If the new car warranty's time ran out by May 16, 2024, the extension's time limit was November 16, 2024.
- Coverage:
- Up to 12 months or 12,000 miles after the new car warranty ends. Ask an Audi dealer for the exact terms.
NHTSA Crash Test Ratings
NHTSA 5-Star Safety Ratings for this model year. See the 2021 A4 ratings on NHTSA.gov.
4-door AWD
allroad AWD
S4 4-door AWD
Check Before You Buy
A checklist for the 2021 A4, from its four recalls, three Audi warranty extensions that may still apply and the problems owners report most.
Confirm the Recalls Were Done
Ask the seller for proof that each of these recalls was repaired.
- Rearview Display Inoperative/FMVSS 111 NHTSA 22V742000
- Rear Axle May Be Misaligned NHTSA 22V034000
- Seat Belt Locking Retractor Malfunction/FMVSS 208 NHTSA 21V606000
- Rear Axle Lock Nuts May Break NHTSA 21V295000
Ask an Audi Dealer
Ask whether each of these warranty extensions applies to this VIN, and whether the work was done.
- AWA-21-01: air conditioning evaporator failure
- AWA-22-05: faulty electric fuel pump
- AWA-24-04: automatic emergency braking system faults
On the Test Drive
- Test the screen, audio and phone connection for freezing or rebooting.
Ask the Seller
Ask whether any of these were ever repaired, and ask to see the receipts.
- Instrument cluster
- Unintended acceleration
- Also ask for the service records, especially oil changes.
Before You Pay
- Get an independent pre-purchase inspection from a mechanic you choose.
- Decode the VIN to confirm the model year, engine and trim.
- Check the title for salvage, flood or rebuilt branding.
What to do next