Model Reports 5 min read Updated 18 Oct 2026

BMW 4 Series 2015: reliability & common MOT faults

In 2025, 80 in every 100 first MOTs on a 2015 BMW 4 Series were passes. Most common reason for a fail: Tyre condition (rear).

Summary

The 2015 BMW 4 Series follows the pattern of the model years either side.

At a glance

How 17,165 first tests went in 2025.

Passed first time
80 in every 100
Did not pass first time
20 in every 1003,419 failed first-attempt tests
The typical car
10 yearsabout 84,768 miles
First tests counted
17,165

What failed most often

  1. Tyre condition (rear)19 in every 100 failed tests
  2. Tyre tread depth (rear)10 in every 100 failed tests
  3. Brake pads (rear)6 in every 100 failed tests

How we count this. Data: UK MOT open data, 2025. Only Class 4 cars on their first MOT of the year are counted. A car that fails and is fixed at the test station still counts as a fail in the first-attempt rate. These are raw results, not adjusted for age, mileage, or peer mix. The MOT does not test engine or gearbox internals.

Note:

These are patterns across 2015 BMW 4 Series vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. A wear pattern follows age and use more than the way the car was built. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Road wheels

One fault: wheel fixings (rear), 4.1 times as often as on similar cars.

Figures below are measured across the 3,418 of 3,419 failed first attempts that recorded an odometer reading in 2025. Mileage is needed to compare like with like.

We only list faults with at least 20 failures and a rate of about 2.0 times that of similar cars, which keeps one-off results out of the list.

Wheel fixings (rear)

Failed on 69 first tests4.1 times as often as similar carsLikely evidence

What it means

Wheel nuts, bolts and studs are the fixings that attach the road wheel. A wheel with a loose or missing wheel nut, bolt or stud is Major. If more than one is loose or missing, it is graded Dangerous.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Tyres

Three wear patterns. The strongest is the tyre condition (rear): 3.1 times as often as on similar cars.

Tyre condition (rear)

Failed on 644 first tests3.1 times as often as similar carsWear pattern

What it means

Exposed or damaged ply or cords are graded Dangerous. A cut in excess of the requirements and deep enough to reach the ply or cords is Major, and testers may open the cut with a blunt instrument to check its depth. A tyre contacting the vehicle through flexing or suspension movement is not a defect; fouling fails only at the time of test.

Tyre tread depth (rear)

Failed on 330 first tests3.0 times as often as similar carsWear pattern

What it means

Only primary grooves count when tread depth is assessed: those holding the wear indicators, or cut as deep as those when new. Shallower secondary grooves are ignored. Tread depth below the minimum for the vehicle is Dangerous, and so is a pattern not visible over the whole tread, but that second row applies only to vehicles that need the lower minimum.

Tyre condition (front)

Failed on 577 first tests2.3 times as often as similar carsWear pattern

What it means

Exposed or damaged ply or cords are graded Dangerous. A cut in excess of the requirements and deep enough to reach the ply or cords is Major, and testers may open the cut with a blunt instrument to check its depth. A tyre contacting the vehicle through flexing or suspension movement is not a defect; fouling fails only at the time of test.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Suspension

Two faults. The strongest is the shock absorbers (rear): 3.0 times as often as on similar cars.

Shock absorbers (rear)

Failed on 214 first tests3.0 times as often as similar carsPossible evidence

What it means

Slight seepage that leaves a film of fluid on a shock absorber does not fail it. Severe leakage, or damage so that it does not function, is Major. A shock absorber missing or likely to become detached is graded Dangerous, though a missing one is only rejected if shock absorbers were fitted as standard.

Shock absorbers (front)

Failed on 141 first tests2.0 times as often as similar carsPossible evidence

What it means

Slight seepage that leaves a film of fluid on a shock absorber does not fail it. Severe leakage, or damage so that it does not function, is Major. A shock absorber missing or likely to become detached is graded Dangerous, though a missing one is only rejected if shock absorbers were fitted as standard.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

Advisories

Other things testers noted as worn or close to failing, more often than on similar cars.

An advisory is a note from the tester about something that has not failed yet. It is an early warning, not a fail.

Transmission oil leaks (rear)

Noted on 60 first tests15 times as often as similar carsElevated evidence

Non-component advisories (front)

Noted on 275 first tests4.1 times as often as similar carsElevated evidence

Data: UK MOT open data, 2025. Counts cover advisories recorded on failed first tests only, compared with cars of the same age and mileage.

MOT pass rates

How first tests ended, and how the pass rates are counted.

Passed first time
80in every 100
Passed on the first test.
Fixed at the station
3in every 100
Failed, then fixed at the test station the same day.
Failed
17in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 80.1% of 17,165 first tests (2025): only cars that passed first time count. Official-style pass 82.8%: cars fixed at the test station also count as a pass. The 3 fixed and the 17 not fixed make the 20 in every 100 that did not pass first time.

Petrol and diesel

First testsTypical mileagePassed first time, as testedPassed first time, same mileage
Diesel13,09490,489 miles7980
Petrol4,07166,513 miles8280

Figures are in every 100 first tests. Cars with more miles usually fail more often, so the same-mileage figure gives every fuel the mileage mix of all the cars in this year.

Same model, other years

Passed first time in every 100, all tested in 2025.

40608010020152020Older carsNewer cars
40608010020152020Newer cars

Newer cars are younger, so look for a jump rather than the climb. A year earlier (2024), when these cars were a year younger, 81 in every 100 passed first time.

YearPassed first timeFirst tests
201377 in every 1001,454
201477 in every 10011,797
2015 This car80 in every 10017,165
201683 in every 10017,416
201784 in every 10016,372
201885 in every 10014,744
201985 in every 1009,724
202087 in every 1004,356
202188 in every 1006,480
202288 in every 1006,811

If you are buying one

What this year's MOT record means for the decision in front of you.

Mileage matters most on a 2015 BMW 4 Series.

Of 2015 BMW 4 Series vehicles with under 60,000 miles, 85 in every 100 passed their 2025 MOT first time. With 113,000 miles or more, 76 in every 100 did.

Under 60,0003,406 tests
85
60,000–77,0003,402 tests
82
77,000–93,000 Typical car3,575 tests
79
93,000–113,0003,403 tests
78
113,000 and over3,377 tests
76

Petrol or diesel?

Typical mileagePassed first time,
as tested		Passed first time,
same mileage
Diesel90,489 miles7980
Petrol66,513 miles8280

Figures are in every 100 first tests. Petrol cars look better on the raw figures only because diesel cars have done more miles (typically 90,489 against 66,513). At the same mileage there is no clear difference between the two.

What to check at your mileage

How often each fault turned up on a failed first test, by the car's mileage. Read it as: what is likely to need looking at on a car like the one in front of you.

Under 60,00077,000–93,000113,000 and over
Tyre condition (rear)3.73.24.2
Tyre tread depth (rear)0.82.02.6
Brake pads (rear)0.91.21.6
Shock absorbers (rear)0.21.42.3
Windscreen washers1.01.51.2

Faults per 100 first tests, by the car's mileage at the test.

When a car fails

51in every 100

of failed cars had one item to fix.

21in every 100

of failed cars had three or more items to fix.

9in every 100

of all first tests had a defect the tester marked dangerous (unsafe to drive away).

Every figure here is a first-attempt MOT rate from DVSA open data for this model line, for cars of this model year tested in 2025. Each mileage band holds a fifth of the tests. MOTs do not test engine or gearbox internals, so this is a pre-purchase checklist, not a full reliability score.

FAQs

Short answers about how to read this model-year guide.

The 2015 BMW 4 Series follows the pattern of the model years either side. Its main cause of failure was Tyre condition (rear), about 19 in every 100 failed tests. In 2025, 80.1% of 17,165 first MOTs on the 2015 BMW 4 Series passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 82.8%. Among 3,419 failed first-attempt MOT tests (test year 2025), Wheel fixings (rear) appears more often than on similar cars (2.0% of those tests; 69 observed failures; about 4.1× more often than similar cars). There is no single reliability score here; this is a pre-purchase checklist built from DVSA open data, not a guarantee for any individual car.
Ranked by how often they were actually recorded, the items that most often failed a 2015 BMW 4 Series at the first attempt were Tyre condition (rear) (18.8%), Tyre tread depth (rear) (9.7%) and Brake pads (rear) (6.3%), each as a share of the year's failed first attempts. That is what goes wrong most often on the car. The common faults table shows a different measure: faults that are unusual compared with similar cars.
Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Wheel fixings (rear) (2.0% of those tests; 69 observed failures; about 4.1× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Wheel fixings (rear) shows up more often than on similar cars (2.0% of those tests; 69 observed failures; about 4.1× more often than similar cars). That does not prove a design fault. Age, mileage, and how the car was used still matter. Treat it as a pre-purchase checkpoint, not a manufacturer service bulletin.
Common MOT problem areas for the 2015 BMW 4 Series include Wheel fixings (rear), Shock absorbers (rear). These are the faults that stand out compared with similar cars, not a complete list of what can go wrong on any individual car.
Advisories flag issues noted at the test and are not a fail rate. We show advisory patterns that appear more often than on similar cars among failed first-attempt tests, separate from common failure rows. Use them as early-warning checks, not as a pass/fail score.
This page highlights MOT failure patterns for the 2015 BMW 4 Series (registration year) using UK DVSA open data for the selected test year. Patterns are compared with cars of a similar age and mileage. It is a buyer checklist from MOT defect statistics, not a full service history or manufacturer service-bulletin list.
No. MOT tests do not cover engine internals, gearboxes, or many electronic modules. Patterns here come from MOT defect statistics only and should not be read as engine or gearbox reliability scores.

About this data

How this page is built and what it can (and can't) say.

These figures come from UK MOT open data for this model year. We surface common failure patterns against similar cars, not a full reliability score, and not a pass/fail verdict on any individual vehicle.

2024 2025

What we include

UK Class 4 cars only. Normal MOT tests (not retests); first test per vehicle per calendar year; results pass, PRS, or fail.

Same-day repairs

PRS means the car failed items that were fixed at the test station and then passed the same day. We count PRS as a first-attempt fail in headline rates so same-day repairs do not hide problems.

How we compare

We compare this model year with other Class 4 cars of similar age and mileage in the same test year. This model family is left out of the peer group so the car is not measured against itself.

What this does not cover

  • MOTs do not cover engine internals, gearboxes, or many electronics; this is not a full reliability score.
  • Common faults come from MOT defect stats, not manufacturer TSBs or recalls.
  • Age and mileage matching reduces, but does not remove, differences in how cars were used and maintained.
  • If the data for a car is too thin to say anything useful, we say so rather than guess.

Contains public sector information licensed under the Open Government Licence v3.0.

Check any vehicle’s MOT history

Full MOT history, mileage records, and reliability insights for any UK vehicle.

Run a free check