Part of the Audi A4 B8 (2008–2015) guide: best and worst years compared.

Used car guide

2009 Audi A4 diesel: common problems and MOT failures

What MOT testers find on the diesel Audi A4 first registered in 2009 (diesel cars only): we looked at the 31,309 MOTs these cars had during 2023–2025. Plus known faults and what to look at before you buy one.

31,309MOTs of 2009 diesel cars, done in 2023–2025
65%pass first time (all 2009 cars: 59%)
9,400typical miles a year
2×the usual rate for suspension arm bushes and joints

What goes wrong more than usual on a 2009 Audi A4 diesel?

Parts flagged at MOT more often on the 2009 Audi A4 diesel than on all cars registered in 2009.

  • Suspension arm bushes and joints2× usual
    Audi A4
    21.1% All 2009 cars
    10.4%

    Failed outright at MOT: 2.6%, against 2.2% of all 2009 cars. The rest were advisories or minor defects.

    Rough price £120–£180 (one arm) ClickMechanic

    At the viewing: Listen for clunks over bumps and feel for the steering wandering. Worn arm bushes show as cracked rubber near the wheels.

  • Drive shaft (CV) joints2.8× usual
    Audi A4
    13.7% All 2009 cars
    4.9%

    Failed outright at MOT: 6.8%, against 2.3% of all 2009 cars. The rest were advisories or minor defects.

    Rough price £60–£350 our estimate

    At the viewing: Drive slowly on full steering lock in both directions and listen for clicking. Look for split rubber boots behind the front wheels.

  • Engine warning light2.3× usual
    Audi A4
    5% All 2009 cars
    2.2%

    Failed outright at MOT: 5%, against 2.2% of all 2009 cars. The rest were advisories or minor defects.

    Rough price £10–£80 our estimate

    At the viewing: Ask a friend to check every light while you work the switches: indicators, brake lights, fog lights and reversing lights.

  • Windscreen1.7× usual
    Audi A4
    5.3% All 2009 cars
    3.2%

    Failed outright at MOT: 0.2%, against 0.1% of all 2009 cars. The rest were advisories or minor defects.

    Rough price £60–£300 our estimate

    At the viewing: Check for chips or cracks in the driver's view.

Better than most

Rigid brake pipes: 0.5% here, against 7.2% of all 2009 cars. Exhaust system: 3.2% here, against 7.9% of all 2009 cars.

Common 2009 Audi A4 diesel MOT failures and advisories

The share of 2009 Audi A4 diesel MOT tests where testers flagged each area, as a fail or an advisory. Rough prices are typical independent-garage costs.

  • Suspension
    43% of testsRough price £120–£400

    At the viewing: Listen for knocks over speed bumps, and look behind each front wheel for a snapped coil spring.

  • Tyres
    36% of testsRough price £70–£150

    At the viewing: Check the tread on all four tyres, including the inside edges, and look for cracks or bulges.

  • Brakes
    26% of testsRough price £150–£350

    At the viewing: Look for a lip on the disc edges and feel for judder or pulling when braking firmly from about 40mph.

  • Lights and electrics
    21% of testsRough price £10–£80

    At the viewing: Ask a friend to check every light, including brake lights and indicators, while you operate them.

  • Driveshafts and joints
    14% of testsRough price £60–£350

    At the viewing: On full steering lock, drive slowly and listen for clicking from the front wheels.

  • Wipers, windscreen and mirrors
    10% of testsRough price £15–£250

    At the viewing: Check for chips in the driver's view, and test the wipers and washers.

Known faults on the 2009 Audi A4 diesel

Reported by owners, mechanics and buying guides for this model and age. Check which engine the car has, as some apply to one engine only.

  • EGR and particulate filter (diesel)

    2.0 TDI diesel

    Diesels can clog the EGR valve and particulate filter, especially with short trips.

    At the viewing: Watch for black smoke, rough idle or warning lights.

    If it needs doing: DPF clean or regeneration, about £160–£500. ClickMechanic

    Source: Euro Premium Parts: Audi A4 B8 reliability guide

  • Worn front suspension bushes

    Front control arm bushes wear early, causing clunks and vague steering.

    At the viewing: Listen over bumps and feel for wander.

    Source: Euro Premium Parts: Audi A4 B8 reliability guide

Questions to ask the seller before buying a 2009 Audi A4 diesel

Ask before you travel to see it. A seller who knows the car will have answers, and receipts.

  1. Any recent work on the suspension arm bushes and joints? (Flagged at MOT 2× as often on the 2009 Audi A4 diesel as on other cars the same age.)
  2. Any recent work on the drive shaft (cv) joints? (Flagged at MOT 2.8× as often on the 2009 Audi A4 diesel as on other cars the same age.)
  3. Any recent work on the engine warning light? (Flagged at MOT 2.3× as often on the 2009 Audi A4 diesel as on other cars the same age.)
  4. Can I see the service history and receipts for any big jobs?

Looking at an Audi A4?

Check the actual car: its own MOT history, mileage and what to ask the seller. Free, no sign-up.

Other years

Every year of the Audi A4 compared

YearMOT testsMost flagged
2026–Too new for MOT data
2025–Too new for MOT data
2024–Too new for MOT data
2023362Tyres 19%
20227,043Tyres 28%
202114,494Tyres 28%
202025,381Tyres 28%
201939,575Tyres 30%
201840,399Tyres 28%
201763,211Tyres 28%
201665,764Tyres 29%
201548,854Tyres 31%
201450,261Tyres 31%
201347,748Tyres 32%
201240,105Tyres 33%
201141,085Suspension 39%
201038,856Suspension 40%
200845,736Suspension 47%
200745,101Suspension 48%
200638,799Suspension 50%
200522,925Suspension 49%
200419,785Suspension 50%
200311,574Suspension 52%
20026,124Suspension 54%
20012,778Suspension 48%
20002,815Suspension 45%
19992,189Suspension 46%
19981,448Suspension 45%
1997812Suspension 49%
1996551Suspension 46%
1995174Brakes 40%

Where this comes from: the DVSA's anonymised results for every MOT test done in Great Britain during 2023–2025, counting the MOTs of Audi A4 cars first registered in 2009. "Flagged" includes advisories, so it isn't the same as a fail rate. How we score