# Audi A4 2017–2024 Problems, Reliability & Repair Costs

Canonical: https://carcasefile.com/vehicles/audi-a4-2017-2024/

> Audi A4 B9 (2017–2024): the water pump leak to check first, S tronic and wastegate issues with real repair costs, best years, and a pre-buy checklist.

Case file · AUDI-A4-2017-2024 · B9 (B9 (8W))

# Audi A4 2017–2024 Common problems, reliability & repair costs

The B9 A4 is the most trustworthy A4 in a long time. The EA888 Gen 3 engine mostly shed the oil-burning reputation of earlier 2.0Ts. What's left is a short, well-documented list: a plastic water pump/thermostat module that seeps coolant, a dual-clutch S tronic that punishes skipped fluid services, and some 2020+ electronics quirks. Buy one with records and it's a genuinely good used German sedan.

[Shop Audi A4 parts on Amazon →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%2BA4%2Bparts) Verified part numbers below Affiliate link to Amazon. We may earn a commission if you buy. Your price is the same, and a commission never changes a verdict.

Case data plate AUDI-A4-2017-2024

Case score
7/10

Best years

2021, 2022, 2023

Avoid

2017 (first model year, highest complaint count of the run; +1 more

Status
Reviewed
Amended 2026-08-30

[How we score →](https://carcasefile.com/methodology/)

Exhibit A · Audi A4 EurovisionNim · [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0) · [Wikimedia](https://commons.wikimedia.org/wiki/File:2017_Audi_A4_(8W%29_sport_quattro_sedan_(2018-10-19%29_02.jpg)

Case verdict At a glance

Case score
7/10

Best years

2021, 2022, 2023, 2024

Years to avoid

2017 (first model year, highest complaint count of the run; +1 more

Worst system

transmission

#1 problem

**S tronic (DL382) shudder / mechatronic failure** · $2,000–$5,000 at an independent shop · typically around 50k–100k mi

Companion pages for this car generation:

📄 Dossier Overview Active Page [📋 Inspection Checklist Field Guide ->](https://carcasefile.com/vehicles/audi-a4-2017-2024/checklist/) [💰 Maintenance Costs 5-Year Ledger ->](https://carcasefile.com/vehicles/audi-a4-2017-2024/cost-to-maintain/) [🩺 Audit a Quote Estimate Case File ->](https://carcasefile.com/estimate-doctor/?vehicle=Audi%20A4)

## Engines

- **EA888 Gen 3 (2.0T ultra)** · 2.0L gasoline, 190 hp
- **EA888 Gen 3 (2.0T)** · 2.0L gasoline, 252 hp
- **EA888 Gen 3 (40 TFSI, mild hybrid)** · 2.0L gasoline, 201 hp
- **EA888 Gen 3 (45 TFSI, mild hybrid)** · 2.0L gasoline, 261 hp

## Transmissions

- **DL382 (S tronic)**· dct, 7-speed
- **manual**, 6-speed

## Drivetrain

FWD / AWD

## Body

sedan, wagon (A4 allroad)

## Trims

Premium, Premium Plus, Prestige, allroad

Parts desk

## Audi A4 part-number cross-reference

Start from the OEM number, then pick the brand you trust. Verified equivalents for the Audi A4 (2017–2024).

Part links go to Amazon, and to eBay where Amazon does not stock the part.
Affiliate links, so we may earn a commission if you buy. Your price is
unchanged, and a commission never changes a verdict.

### Oil filter

All B9 A4 2.0T (EA888 Gen 3), 2017-2024
swipe →

OEM part
Audi/VAG
[Find Audi/VAG oil filter on Amazon](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B06L115562B)

Cross-ref Verified fit · 07.26

Mann-Filter
[Look up Mann-Filter oil filter](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fdp%2FB07P9DZS9K)

Cross-ref Verified fit · 07.26

Hengst

cartridge; also crosses 06K115562 / 06L115562 / 06L115562E
[Check Hengst oil filter](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DHengst%2BE358H03D246)

Verified via: [Audi genuine 06L-115-562-B (2014-2026 apps)](https://www.audiusaparts.com/oem-parts/audi-oil-filter-6l115562b), [FCP Euro - Mann HU6013Z for 06L115562](https://www.fcpeuro.com/products/vw-audi-oil-filter-a4-a6-q5-q7-mann-06l115562)

### Engine air filter

quattro cars (252 hp 2.0T, 45 TFSI, 40 TFSI quattro)
swipe →

OEM part
Audi/VAG
[See Audi/VAG engine air filter on Amazon](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B8W0133843C)

Cross-ref Verified fit · 07.26

Mann-Filter
[Compare Mann-Filter engine air filter](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DMann-Filter%2BC%2B17%2B013)

Verified via: [Europa Parts - 8W0133843C fits A4/A5/Q5 B9 2.0T (Mann C17013)](https://www.europaparts.com/air-filter-8w0133843c.html), [Pelican Parts - Mann C 17 013 = 8W0133843C](https://www.pelicanparts.com/More_Info/8W0133843C.htm?pn=8W0-133-843-C-M63)

### Engine air filter

FWD cars only - 2.0T 'ultra' 190 hp and 40 TFSI FWD (engine code DBPA)
swipe →

OEM part
Audi/VAG
[Find Audi/VAG engine air filter on Amazon](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B8W0133843E)

Cross-ref Verified fit · 07.26

Mann-Filter

FWD-specific airbox - do NOT fit the quattro 8W0133843C to a FWD car; confirm by VIN/airbox
[Look up Mann-Filter engine air filter](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fdp%2FB0755B6848)

Verified via: [Europa Parts - 8W0133843E for A4 B9 2.0T FWD, DBPA](https://www.europaparts.com/air-filter-8w0133843e.html), [eBay - Mann 8W0133843E / C 17 012/1, Audi A4 2017-2020](https://www.ebay.com/itm/353093077688)

### Cabin air filter

All B9 A4 2017-2024 (curved B9 filter; the flat B8 CUK2450 does not fit)
swipe →

OEM part
Audi/VAG

current activated-charcoal filter; supersedes 4M0819439A, cross-listed 8W0819439A
[Check Audi/VAG cabin air filter on Amazon](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B4M0819439B)

Cross-ref Verified fit · 07.26

Mann-Filter

activated carbon; = OE 4M0819439A/B
[See Mann-Filter cabin air filter](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fdp%2FB073WXFY8P)

Verified via: [Audi genuine 4M0819439B - 2021 A4](https://parts.audiusa.com/p/Audi_2021_A4/Cabin-Air-Filter/70098137/4M0819439B.html), [UroTuning - Mann cabin filter 4M0819439B (B9 A4/A5/Q5)](https://www.urotuning.com/products/cabin-air-filter-audi-b9-a4-a5-q5-s4-s5-sq5-more-4m0819439b-man)

### Spark plugs

Set of 4; all B9 A4 2.0T EA888 Gen 3 (2017-2024, incl. 40/45 TFSI mild hybrid)
swipe →

OEM part
Audi/VAG (NGK or Bosch OE)

dual-vendor OE plug for the A4 2.0T
[Compare Audi/VAG spark plugs on Amazon](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B%2528NGK%2Bor%2BBosch%2BOE%2529%2B06K905601B)

Cross-ref Verified fit · 07.26

NGK

NGK stock 94833; factory-gap 0.8 mm
[Find NGK spark plugs](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DNGK%2BPLFER7A8EG)

Cross-ref Verified fit · 07.26

Bosch

OE-type double-platinum; factory-gap 0.7 mm
[Look up Bosch spark plugs](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fdp%2FB00L7YHB5A)

Verified via: [Audi genuine 06K905601B - A4 2.0T (NGK/Bosch OE)](https://parts.audiusa.com/p/Audi__A4/Spark-Plug-Spark-Plug-Optional-Spark-Plug-VendorNGK/54564583/06K905601B.html), [Pelican Parts - NGK PLFER7A8EG / Bosch 8160 = 06K905601B](https://www.pelicanparts.com/More_Info/06K905601B.htm?pn=06K-905-601-B-M220)

### Front brake pads

314 x 25 mm front rotor (PR code 1LA/1LB) - the volume A4 2.0T fitment
swipe →

OEM part
Audi/VAG

current; supersedes 8W0698151AF. Higher trims / S line use 318 mm (PR 1LC/1LD) or 338 mm (PR 1LE/1LF) with different pads - verify the PR code before ordering
[Check Audi/VAG front brake pads on Amazon](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B8W0698151BH)

Cross-ref Verified fit · 07.26

Textar

OE refs 8W0698151AD/BC
[See Textar front brake pads](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DTextar%2B2240201)

Cross-ref Verified fit · 07.26

ATE

ceramic; OE ref 8W0698151BB
[Compare ATE front brake pads](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DATE%2B607329)

Verified via: [Audi genuine 8W0698151BH - front pads 314x25 mm (2017-2025 A4)](https://parts.audiusa.com/p/Audi__A4/Disc-Brake-Pad-Set-Front/105708041/8W0698151BH.html), [Strictly European Motors - Textar 2240201 (front, B9 A4)](https://strictlyeuropeanmotors.com/products/front-brake-pads-textar-2240201)

### Wiper blades

Front pair; B9 A4 uses a push-button (bayonet) arm
swipe →

OEM part
Audi

size spec; any beam blade with the Audi push-button adapter fits
[Find Audi wiper blades on Amazon](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%2B24%2Bin%2B%2528600%2Bmm%2529%2Bdriver%2B%252B%2B20%2Bin%2B%2528500%2Bmm%2529%2Bpassenger)

Cross-ref Verified fit · 07.26

Michelin
[Look up Michelin wiper blades](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DMichelin%2BStealth%2BUltra%2B24%2522%2B%252B%2B20%2522)

Verified via: [Wipersized - Audi A4 wiper sizes 24"/20"](https://www.wipersized.com/audi/a4/), [Amazon - A4 B9 push-button beam blades 24"+20" (2015-2024)](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2FIULMTYN-Blades-2015-2024-Button-Windshield%2Fdp%2FB0DQGZR3MD&raw=1)

### Serpentine belt

2017-2019 2.0T (non-mild-hybrid): 190 hp ultra, 252 hp 2.0T, 6-spd manual
swipe →

OEM part
Audi/VAG

6-rib poly-V, ~1132 mm (6PK1132). 2020+ 40/45 TFSI cars use a belt-driven starter-generator (mild hybrid); that accessory-belt number was not independently confirmed here - verify by VIN before ordering
[Check Audi/VAG serpentine belt on Amazon](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B06L903137A)

Cross-ref Verified fit · 07.26

Continental
[See Continental serpentine belt](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DContinental%2B6K1130)

Verified via: [Audi genuine 06L903137A - 2017 A4 poly-V belt](https://parts.audiusa.com/p/Audi_2017_A4/Serpentine-Belt/54671690/06L903137A.html), [WPD USA - Continental 6K1130 = 06L903137A](https://www.wpdusa.com/products/22784/Serpentine-Belt-Continental-6K1130-VW-Audi-06L903137A)

### Battery (BCI group)

All B9 A4; AGM required
swipe →

OEM part
Audi (VARTA OE)

group size rises to H7 (BCI 94R) or larger on more-equipped cars - check the tray. A replacement must be coded to the energy-management/BMS (VCDS/OBDeleven). 2020+ mild-hybrid cars add a separate small 12 V auxiliary battery
[Compare Audi battery on Amazon](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%2B%2528VARTA%2BOE%2529%2BH6%2B%252F%2BBCI%2Bgroup%2B48%252C%2BAGM)

Cross-ref Verified fit · 07.26

Interstate
[Find Interstate battery](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DInterstate%2BMTZ-48%2B%2528H6%252C%2BAGM%2529)

Cross-ref Verified fit · 07.26

Duralast/other

for cars fitted with the larger H7 tray
[Look up Duralast/other battery](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DDuralast%252Fother%2BGroup%2B94R%2BAGM)

Verified via: [Interstate - MTZ-48/H6 AGM listed for A4 quattro](https://www.interstatebatteries.com/products/mtz-48/h6/2016-audi-a4-quattro-l420l-pr-code-j0l), [AutoZone - Audi A4 battery, group 94R option (2017)](https://www.autozone.com/batteries-starting-and-charging/battery/audi/a4/2017/b/group-size/94r)

Amazon and eBay affiliate links. Prices unchanged for you. Confirm fitment against your VIN; mid-generation changes exist.

Verdict

## Should I buy a 2017–2024 Audi A4?

Buy it with records. The B9 is the A4 generation where Audi fixed most of what plagued the B8: oil consumption is far tamer, the timing chain tensioner drama is gone, and there's no Takata airbag baggage. The two things that decide whether a specific car is a good buy are cooling-system history (the plastic water pump/thermostat module leaks, and the 8-year/80,000-mile extended warranty from the class settlement has expired or nearly expired on most cars) and S tronic service history (fluid every ~40k miles, no low-speed shudder on the test drive). A 2021–2024 facelift car with both boxes checked is an easy recommendation. Walk away from any B9 with no service paperwork. German-car deferred maintenance is exactly how these become money pits.

Best years

2021, 2022, 2023, 2024

Years to avoid

2017 (first model year, highest complaint count of the run; verify water pump/thermostat service and recall completion), Any year with no S tronic fluid-service records

Inspection Companion

### Pre-Purchase Checklist for Audi A4

[Open Field Checklist Page ->](https://carcasefile.com/vehicles/audi-a4-2017-2024/checklist/)

- ☐ Check the coolant reservoir level and look for pink/white crusty residue around the water pump/thermostat housing at the front of the engine. Slow seepage with no puddle is the classic EA888 Gen 3 failure.
- ☐ Ask by VIN (Audi dealer or audiusa.com/recall) whether the water pump/thermostat module was already replaced under the 8-yr/80k extended warranty, and whether open recalls (backup camera software on 2020–2022, seat-heater cable/passenger airbag on 2017–2020) are done.
- ☐ On the test drive, creep in stop-and-go traffic and reverse up a slight incline. Low-speed shudder or clunky engagement points to S tronic clutch or mechatronic trouble.
- ☐ Get proof of S tronic fluid services (roughly every 40,000 miles). No records on a 60k+ car = budget for the service immediately and negotiate.
- ☐ Listen at light throttle between roughly 1,500–3,000 rpm for a tinny metallic rattle, the known wastegate-linkage rattle. Usually cosmetic, but note it and check for boost codes.
- ☐ Check the oil level in the MMI and ask directly about top-offs between changes. Gen 3 engines are much better than older 2.0Ts, but some cars still use a noticeable amount.
- ☐ On 2020+ mild-hybrid cars, confirm start-stop works normally and no battery warnings appear in the MMI. Auxiliary-battery and battery-management faults are a known annoyance.
- ☐ On the allroad, confirm the rear-axle alignment follow-up recall was performed if the car had earlier recall work.

Verified-fit parts for the Audi A4 (2017–2024).

Parts desk

Parts cross-reference

OEM number first, verified equivalents below it. Links go to Amazon.

Oil filter

All B9 A4 2.0T (EA888 Gen 3), 2017-2024

- [OEM Audi/VAG 06L115562B →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B06L115562B)
- [Mann-Filter HU 6013 z →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fdp%2FB07P9DZS9K)
- [Hengst E358H03D246 →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DHengst%2BE358H03D246)

Engine air filter

quattro cars (252 hp 2.0T, 45 TFSI, 40 TFSI quattro)

- [OEM Audi/VAG 8W0133843C →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B8W0133843C)
- [Mann-Filter C 17 013 →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DMann-Filter%2BC%2B17%2B013)

Engine air filter

FWD cars only - 2.0T 'ultra' 190 hp and 40 TFSI FWD (engine code DBPA)

- [OEM Audi/VAG 8W0133843E →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B8W0133843E)
- [Mann-Filter C 17 012/1 →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fdp%2FB0755B6848)

Cabin air filter

All B9 A4 2017-2024 (curved B9 filter; the flat B8 CUK2450 does not fit)

- [OEM Audi/VAG 4M0819439B →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B4M0819439B)
- [Mann-Filter CUK 31003 →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fdp%2FB073WXFY8P)

Spark plugs

Set of 4; all B9 A4 2.0T EA888 Gen 3 (2017-2024, incl. 40/45 TFSI mild hybrid)

- [OEM Audi/VAG (NGK or Bosch OE) 06K905601B →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B%2528NGK%2Bor%2BBosch%2BOE%2529%2B06K905601B)
- [NGK PLFER7A8EG →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DNGK%2BPLFER7A8EG)
- [Bosch 8160 →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fdp%2FB00L7YHB5A)

Front brake pads

314 x 25 mm front rotor (PR code 1LA/1LB) - the volume A4 2.0T fitment

- [OEM Audi/VAG 8W0698151BH →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B8W0698151BH)
- [Textar 2240201 →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DTextar%2B2240201)
- [ATE 607329 →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DATE%2B607329)

Wiper blades

Front pair; B9 A4 uses a push-button (bayonet) arm

- [OEM Audi 24 in (600 mm) driver + 20 in (500 mm) passenger →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%2B24%2Bin%2B%2528600%2Bmm%2529%2Bdriver%2B%252B%2B20%2Bin%2B%2528500%2Bmm%2529%2Bpassenger)
- [Michelin Stealth Ultra 24" + 20" →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DMichelin%2BStealth%2BUltra%2B24%2522%2B%252B%2B20%2522)

Serpentine belt

2017-2019 2.0T (non-mild-hybrid): 190 hp ultra, 252 hp 2.0T, 6-spd manual

- [OEM Audi/VAG 06L903137A →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%252FVAG%2B06L903137A)
- [Continental 6K1130 →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DContinental%2B6K1130)

Battery (BCI group)

All B9 A4; AGM required

- [OEM Audi (VARTA OE) H6 / BCI group 48, AGM →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DAudi%2B%2528VARTA%2BOE%2529%2BH6%2B%252F%2BBCI%2Bgroup%2B48%252C%2BAGM)
- [Interstate MTZ-48 (H6, AGM) →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DInterstate%2BMTZ-48%2B%2528H6%252C%2BAGM%2529)
- [Duralast/other Group 94R AGM →](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3DDuralast%252Fother%2BGroup%2B94R%2BAGM)

Confirm fitment against your VIN. Mid-generation changes exist. Affiliate links. We may earn a commission at no cost to you.

Known faults

## Common Audi A4 problems & repair costs

### Water pump / thermostat module coolant leak (EA888 Gen 3)

$700–$1,500

cooling moderate 2017–2024 (highest reported incidence on early cars) ~40k–90k mi

**Symptoms:** Coolant level that drifts down over weeks with no puddle; sweet smell after shutdown; pink or white crusty residue around the plastic pump/thermostat housing on the front of the block; eventually a low-coolant warning.

**Fix:** Replace the combined water pump/thermostat module (it's one plastic assembly) and refill/bleed the system. A class-action settlement extended coverage to 8 years / 80,000 miles from in-service date. Worth checking by VIN, but that window has closed or nearly closed on most B9s, so price it as an owner-pays repair.

Sources: [VAG Manchester: EA888 Gen 3 thermostat/water pump housing leak](https://vagmanchester.com/article/common-faults-vag-ea888-gen-3-engine-thermostat-and-water-pump-housing-leak/), [CarComplaints: 2017 Audi A4 (thermostat housing/water pump leak, ~$800 avg at ~52k mi)](https://www.carcomplaints.com/Audi/A4/2017/), [Audizine: 'Anyone Have to Replace Water Pump/Thermostat Housing Yet?' (B9)](https://www.audizine.com/forum/showthread.php/999087-Anyone-Have-to-Replace-Water-Pump-Thermostat-Housing-Yet)

### S tronic (DL382) shudder / mechatronic failure

$2,000–$5,000

transmission severe 2017–2024 ~50k–100k mi

**Symptoms:** Shudder or judder creeping from a stop or engaging reverse, delayed or harsh engagement, warning lights with clutch-slip or parking-lock fault codes. Diagnosis sometimes finds clutch material in the fluid.

**Fix:** Mild cases respond to a fluid-and-filter service; confirmed mechatronic failure means replacing or rebuilding the mechatronic unit, and worn clutch packs add more. Prevention is cheap: service the fluid every ~40k miles. This is not an epidemic, and most B9 S tronics live long lives, but it's the most expensive realistic failure on this car.

Sources: [Audizine: B9 transmission shudder and mechatronic replacement](https://www.audizine.com/forum/showthread.php/858877-B9-S4-Transmission-shudder-and-mechatronic-replacement), [Eco Torque: Audi DL382 mechatronic failures, fault codes and fixes](https://eco-torque.co.uk/blogs/news/audi-dl382-mechatronic-failures-0ck-0cl-0cj-symptoms-fault-codes-repairs)

### Turbo wastegate rattle

$50–$2,800

engine minor 2017–2024 ~any

**Symptoms:** Tinny metallic rattle at light throttle, most audible below ~35 mph between roughly 1,500–3,000 rpm. Caused by free play in the wastegate actuator linkage.

**Fix:** Usually just noise: an Audi anti-rattle clip (part 06J145220A) or actuator-rod adjustment quiets most cars for very little money. The caveat: a loose, worsening wastegate can eventually mean a failing turbo. If the rattle comes with boost codes (P0299) or power loss, budget for a turbo replacement at the high end of the range.

Sources: [AudiWorld: A4 B9 wastegate rattle thread](https://www.audiworld.com/forums/a4-b9-platform-discussion-212/a4-b9-waste-gate-rattle-3011468/), [Audizine: wastegate anti-rattle clip](https://www.audizine.com/threads/wastegate-anti-rattle-clip.835793/)

### Oil consumption (much improved, not extinct)

$150–$500

engine moderate 2017–2024 ~20k+ mi

**Symptoms:** Oil level dropping between changes. Some owners report half a quart to a quart per 5,000 miles developing after the first 20k. No smoke, no leak.

**Fix:** First step is cheap: monitor consumption formally and replace the PCV valve if it's worn. That resolves many cases. The Gen 3 EA888 largely fixed the piston-ring design that made 2009–2016 2.0Ts notorious, so severe ring-related burning is uncommon on the B9. A car using a quart per 1,000 miles needs a compression/leak-down diagnosis before you buy it, not after.

Sources: [AudiWorld: 2018 A4 2.0T oil consumption thread](https://www.audiworld.com/forums/a4-b9-platform-discussion-212/2018-a4-2-0t-oil-consumption-2959102/), [Audizine: new info on 2.0T oil consumption](https://www.audizine.com/forum/showthread.php/959075-(Possibly%29-New-info-on-2-0T-oil-consumption)

### Electronics: backup-camera recalls, 12V mild-hybrid battery faults, MMI glitches

$0–$600

electrical minor 2017–2024 (mild-hybrid faults 2020+ only) ~any

**Symptoms:** Blank or black screen instead of the rear-view image in reverse (recalled on 2020–2022 cars); auxiliary-battery or battery-management warnings and balky start-stop on 2020+ mild hybrids; occasional blank MMI screens and parasitic battery drain reports across the run.

**Fix:** The backup-camera problem was handled by NHTSA recalls. Dealers updated or replaced the infotainment unit free, so just verify completion by VIN. Mild-hybrid battery faults typically end in a 12V auxiliary battery replacement with proper coding. MMI oddities often clear with a software update. Annoyances, not wallet-killers.

Sources: [Cars.com: Audi A4 recalls (rear-view camera software, 2021–2022)](https://www.cars.com/research/audi-a4/recalls/), [Audizine: 2020 A4 B9 12V mild-hybrid auxiliary battery fault](https://www.audizine.com/threads/2020-audi-a4-b9-12v-mild-hybrid-auxiliary-battery-fault.1006935/), [CarComplaints: 2017 A4 electrical complaints](https://www.carcomplaints.com/Audi/A4/2017/electrical/)

Budget German-premium, not Honda, money: synthetic oil changes run $120–$180 at an independent shop, the S tronic fluid service is $350–$600 every ~40k miles (do not skip it; see the mechatronic problem above), and the engine wants 91+ octane. Brakes, suspension bushings, and tires cost more than the equivalent Camry parts but nothing exotic. The realistic big-ticket items are the water pump module (mid-hundreds to $1,500) and, rarely, S tronic internals. A B9 bought with full records and given fluids on time is one of the cheaper German sedans to actually live with.

Cost calculator

### What will this Audi A4 cost you by a given mileage?

Drag to a mileage. We total the documented problems whose typical onset falls at or before it. The same cost ranges listed above, nothing new invented.

100k mi

$0 estimated repair range

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Have a repair quote for this Audi A4?

Audit against OEM book times, uncover duplicate pad and rotor labor, and verify parts markups.

[Audit Repair Estimate ->](https://carcasefile.com/estimate-doctor/?vehicle=Audi%20A4)

DIY repairs

## How to fix common Audi A4 problems (DIY)

### Engine & cabin air filter replacement

easy 30 min saves ~$80–$150

**Tools:** T25 Torx driver (airbox screws), Trim tool or flathead (glovebox area)

- Open the hood and remove the Torx screws holding the airbox lid, then lift the lid and swap in the new engine filter with the seal seated all the way around.
- Re-seat the lid and snug the screws. Don't overtighten plastic.
- For the cabin filter, open the passenger footwell cover under the glovebox and release the filter door.
- Slide the old cabin filter out, note the airflow arrow, and insert the new one the same direction.
- Close the filter door and cover, then confirm the blower sounds normal on high.

Parts

- [Engine air filter (Audi A4 B9 2.0T)](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3D2017-2024%2Baudi%2Ba4%2Bengine%2Bair%2Bfilter) · Amazon $15–$30
- [Cabin air filter (Audi A4 B9)](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3D2017-2024%2Baudi%2Ba4%2Bcabin%2Bair%2Bfilter) · Amazon $12–$25

### Spark plug replacement (2.0T)

moderate 1–1.5 hrs saves ~$150–$300

**Tools:** Ratchet with 14mm thin-wall spark plug socket, T30 Torx (coil cover/harness brackets as needed), Torque wrench, Coil puller or gentle twisting by hand

- With the engine cold, remove the engine cover and unplug each ignition coil connector.
- Pull the four coils straight up, twisting gently if stuck. Don't pry the boot.
- Blow out the plug wells before removing plugs so debris can't fall into the cylinders.
- Remove the old plugs, thread the new ones in by hand, then torque to spec (roughly 18 ft-lb, verify for your plug).
- Re-seat coils and connectors, refit the cover, and check for smooth idle.

Parts

- [Spark plugs, set of 4 (Audi A4 2.0T)](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3D2017-2024%2Baudi%2Ba4%2B2.0t%2Bspark%2Bplugs) · Amazon $30–$60

### Front brake pads

moderate 1.5–2.5 hrs saves ~$200–$400

**Tools:** Floor jack + jack stands, 17mm socket / breaker bar (wheel bolts), 13mm and 21mm for caliper hardware (verify on your car), Caliper piston compressor or large C-clamp, Wire brush and brake grease

- Loosen wheel bolts, jack the car, set stands, and remove the front wheels.
- Unbolt the caliper from its carrier and hang it. Never let it dangle by the hose.
- Remove old pads, clean the carrier contact points with a wire brush, and grease them lightly.
- Compress the piston slowly (crack the reservoir cap first), fit the new pads, and re-bolt the caliper to spec.
- Refit wheels, torque the bolts, then pump the pedal firm BEFORE driving and bed the pads gently for the first 100 miles.

Parts

- [Front brake pads (Audi A4 B9)](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3D2017-2024%2Baudi%2Ba4%2Bfront%2Bbrake%2Bpads) · Amazon $40–$90
- [Brake pad wear sensor (front)](https://carcasefile.com/go?u=https%3A%2F%2Fwww.amazon.com%2Fs%3Fk%3Daudi%2Ba4%2Bb9%2Bfront%2Bbrake%2Bwear%2Bsensor) · Amazon $8–$20

Some parts links are affiliate links. We may earn a commission at no cost to you. We only list parts that fit this generation.

## The short version

The B9 A4 is the generation where Audi cleaned up its act. The 2.0-liter EA888 Gen 3 engine that powers every US car largely fixed the oil consumption and timing-chain problems that made the 2009–2016 A4 a gamble. There’s no Takata airbag cloud over it, and no single catastrophic defect defines the car.

What it has instead is a short list of known, checkable issues. The plastic **water pump/thermostat module** likes to seep coolant, slowly and with no puddle, usually somewhere between 40k and 90k miles. It was common enough to produce a class-action settlement with an 8-year/80,000-mile extended warranty, a window that has now closed on most B9s. The **7-speed S tronic dual-clutch** is durable when its fluid is changed every ~40k miles and expensive when it isn’t. A failed mechatronic unit is a $2,000–$5,000 job. And many cars make a tinny **wastegate rattle** at light throttle that’s usually just noise.

## What that means when you’re shopping

Three checks separate the good buys from the money pits. First, pop the hood: look for low coolant and pink crust around the pump housing, and ask a dealer to run the VIN for the extended-warranty repair and open recalls. Second, demand S tronic fluid-service records and test-drive in stop-and-go traffic. Creeping shudder or clunky reverse engagement is your cue to walk. Third, check the oil level and ask about top-offs between changes.

Year-wise, the 2021–2024 facelift cars are the sweet spot: more power, better MMI, recalls sorted. The 2018–2019 cars are the value picks. 2017 logged the most complaints as the first model year, so inspect harder, not never.

## The 2020 facelift, briefly

The facelift brought the 12-volt mild-hybrid start-stop system (40 TFSI and 45 TFSI). It works fine on most cars, but auxiliary-battery and battery-management faults are a known annoyance, and 2020–2022 cars were recalled for backup-camera software that could black out the screen in reverse. Both are cheap or free to sort. Just verify they’ve been sorted.

If you want the 6-speed manual, it exists only in 2017–2018 quattro cars and commands a premium.

**How this file is built:** failure modes and cost ranges are compiled from NHTSA recall data, CarComplaints.com owner reports, the VW/Audi water-pump class settlement, and owner reporting on Audizine and AudiWorld, then sanity-checked against shop-floor experience. Cost figures are independent-shop estimates and vary by region. Spot something off? [Tell us](https://carcasefile.com/disclaimer/).

Myths, checked

## Viral car myths, checked against this car

Misleading

### [Is the "$2 liquid that stops any leak" really banned in 11 states?](https://carcasefile.com/claims/2-dollar-stop-leak-banned-11-states/)

Automotive stop-leak products are not banned in any US state. The products are real (Bar's Leaks, BlueDevil), they work in specific narrow situations, and they can permanently damage your cooling or oiling system if applied to the wrong leak.

Outdated

### [Does a "$1 mineral" really double car battery life? The Epsom-salt reality.](https://carcasefile.com/claims/1-dollar-mineral-doubles-battery-life-myth/)

The mineral is Epsom salt (magnesium sulfate). It was a real desulfation hack for serviceable flooded-cell batteries 40+ years ago. It does not work on modern sealed AGM or EFB batteries, and trying it on yours will void the warranty without helping the battery.

Dangerous

### [Is the "$2 liquid that destroys engine sludge forever" real? Our shop-floor verdict.](https://carcasefile.com/claims/2-dollar-engine-sludge-destroyer-liquid/)

An aggressive solvent flush on a high-mileage engine is a textbook way to spin a bearing. The viral 'kitchen-cabinet flush' is folklore that real shops spend money cleaning up after.

Appendix

## Frequently asked questions

### Is the 2017–2024 Audi A4 reliable?

By German-sedan standards, yes. This is the best A4 generation in years. The Gen 3 EA888 engine fixed most of the oil-burning and timing-chain problems that hurt the 2009–2016 cars. The remaining risks are specific and checkable: the water pump/thermostat coolant seep, S tronic fluid neglect, and some 2020+ electronics gremlins. Condition and records matter more than model year.

### Which B9 A4 years are best?

The 2021–2024 facelift cars: more power (201 or 261 hp), updated MMI, and the backup-camera software recalls already addressed. 2018–2019 are also solid picks and cheaper. 2017 isn't a bad year, but as the first model year it logged the most complaints. Inspect the cooling system and confirm recall completion.

### Is the S tronic dual-clutch transmission a problem?

Mostly no. The 7-speed DL382 behaves differently from a torque-converter automatic, and slight low-speed hesitation is normal, but genuine shudder, harsh engagement, or fault codes are not. Failures concentrate on cars that skipped the ~40k-mile fluid service. A mechatronic replacement runs $2,000–$5,000, so test-drive in stop-and-go traffic and demand service records.

### Is the water pump leak covered by warranty?

A class-action settlement extended coverage on the water pump, thermostat, and housing to 8 years / 80,000 miles from the in-service date. Early B9s are now past that window; late cars may still qualify. An Audi dealer can check your VIN. If it's expired, an independent shop typically charges $700–$1,500 for the module replacement.

### Does the Takata airbag recall affect this A4?

No. The Takata recalls covered older Audis (roughly 2005–2014 model years); the B9 generation isn't included. The airbag-adjacent recall to verify instead is the 2017–2020 seat-heater cable issue that could disable the front passenger airbag. A free dealer fix, checkable by VIN.

Cross-reference

## Every Audi A4 generation

The full case file run, beyond the generation before and after this one.

- [Audi A4 2005–2008 5/10](https://carcasefile.com/vehicles/audi-a4-2005-2008/)
- [Audi A4 2009–2016 4/10](https://carcasefile.com/vehicles/audi-a4-2009-2016/)

## Cross-shopped rivals

Files on what buyers weigh against the Audi A4 of this era.

- [BMW 5 Series 2017–2023 7/10](https://carcasefile.com/vehicles/bmw-5-series-2017-2023/)
- [BMW 3 Series 2019–2026 7/10](https://carcasefile.com/vehicles/bmw-3-series-2019-2026/)

Spot an error in this case file?

Wrong cost, a fault we missed, or a part number that doesn't fit. Tell us and we'll fix it. See our [verification methodology](https://carcasefile.com/methodology/) and [corrections policy](https://carcasefile.com/disclaimer/).

Reviewed CarCaseFile editorial · filed 2026-07-03 · updated 2026-08-30

Cost figures are independent-shop estimates and vary by region and condition. Always confirm a diagnosis before authorizing repairs.