Is the BMW 4 Series reliable?

On MOT evidence the BMW 4 Series is well above average. It passes 83.2% of tests once age and mileage are accounted for, against a national average of 72.3%. That figure covers 77% of the national age and mileage range, which is enough to quote but not to rank. This measures how often the car meets the MOT standard, not how often it breaks down or what a repair costs.

What is the most common MOT failure on a BMW 4 Series?

The item recorded most often is "A tyre cords visible or damaged", which appears in 18.7% of failed BMW 4 Series tests. Because one failed test can list several items, these shares do not add up to 100%.

What do testers most often warn about on a BMW 4 Series?

The most common advisory is "Tyre tread depth not in accordance with the requirements", noted on 25.0% of all BMW 4 Series tests. An advisory is not a failure: it flags something that will likely need attention before the next test.

What mileage does a BMW 4 Series usually have at its MOT?

The average odometer reading recorded at test is 67,269 miles. This is the mileage across all tested examples of every age, not an annual figure, so treat it as a description of the fleet rather than a target for one car.

Does a BMW 4 Series get harder to pass as it ages?

Yes. At 3 to 5 years old, 88.1% of BMW 4 Series tests pass. By 12 to 14 years, that falls to 77.0%. Nearly every model follows this pattern, which is why comparing raw pass rates between models is misleading unless age is accounted for.

Are most BMW 4 Series models petrol or diesel?

Of the BMW 4 Series cars tested, 56% are diesel, 38% are petrol, 3% are diesel hybrid. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

Model reliability file

BMW 4 Series MOT pass rate & common failures

From 111,799 recorded MOT tests of the BMW 4 Series, published by DVSA.

Data updated 29 July 2026

Quick answer

The BMW 4 Series passes 83.2% of MOT tests once results are adjusted for the age and mileage of the cars tested, against a national average of 72.3%. That is well above average. Based on 111,799 tests. Its most commonly recorded failure is tyre cords visible or damaged, which appears in 18.7% of failed tests. Cars of this model average 67,269 miles on the odometer when tested.

At a glance

Pass rate, adjusted for age and mileage

83.2%national average72.3%unadjusted83.5%range covered77%

The 4 Series is 10.9 percentage points above the national pass rate once age and mileage are accounted for, which is well above average. The unadjusted figure is 83.5%; the difference is what the age and mileage of this model’s fleet was hiding.

DVSA recorded wording

Most common failure items

Share of failed BMW 4 Series tests in which each item was recorded. One failed test often lists several items, so these do not sum to 100%.

1.A tyre cords visible or damaged18.7%
3,005 occurrencesTyre ply or cord exposed, or the casing separating explained
2.Tyre tread depth not in accordance with the requirements17.5%
2,812 occurrencesTyre worn close to the legal limit explained
3.A tyre seriously damaged16.8%
2,693 occurrencesTyre damaged or deteriorated explained
4.A tyre seriously damaged12.2%
1,964 occurrencesTyre damaged or deteriorated explained
5.A shock absorber damaged to the extent that it does not function or showing signs of severe leakage10.6%
1,696 occurrencesShock absorber defective explained
6.A brake lining or pad worn below 1.5mm8.7%
1,390 occurrencesBrake drum or shoe worn or contaminated explained
7.Windscreen washers not working or not providing sufficient fluid to clear the windscreen5.4%
871 occurrencesWiper or washer not working properly explained
8.A suspension pin, bush or joint excessively worn5.0%
807 occurrencesSuspension arm bush worn explained
9.A wheel with a loose or missing wheel nut, bolt or stud3.6%
573 occurrencesWheel nut, bolt or stud missing, loose or damaged explained
10.Any fracture or welding defect on a wheel3.5%
555 occurrencesRoad wheel damaged, distorted or cracked explained

Warnings without a failure

Most common advisories

Share of all BMW 4 Series tests carrying each advisory. The denominator differs from the failure list above because an advisory can be issued on a car that passed.

1.Tyre tread depth not in accordance with the requirements25.0%
27,954 testsTyre worn close to the legal limit explained
2.A brake lining or pad worn below 1.5mm9.0%
10,056 testsBrake drum or shoe worn or contaminated explained
3.Brake disc or drum excessively weakened, insecure or fractured8.5%
9,470 testsBrake disc worn, pitted or scored explained
4.A suspension pin, bush or joint excessively worn4.7%
5,302 testsSuspension arm bush worn explained
5.Play in steering rack inner joint(s)3.9%
4,340 tests
6.A shock absorber damaged to the extent that it does not function or showing signs of severe leakage3.7%
4,103 testsShock absorber defective explained
7.A tyre seriously damaged3.5%
3,912 testsTyre damaged or deteriorated explained
8.Tyre tread depth not in accordance with the requirements3.5%
3,884 testsTyre worn close to the legal limit explained

How wear changes the picture

Pass rate by vehicle age

3–5 yrs88%

6–8 yrs85%

9–11 yrs81%

12–14 yrs77%

Bands holding too few tests to be meaningful are omitted rather than shown as a rate.

What gets tested

The 4 Series fleet

Average mileage recorded at test: 67,269
Fuel mix of tested cars: Diesel55.9%
Petrol38.4%
Diesel hybrid3.4%
Hybrid2.3%

Trim names grouped into this model (19)

Recorded exactly as DVSA holds them. Trim-level names are rolled up so one model is not split across a dozen thin pages.

420D M SPORT MHEV AUTO
420D M SPORT PRO ED MHEV AUTO
420D XDRIVE M SPORT MHEV AUTO
420I GRAN COUPE M SPORT AUTO
420I M SPORT
420I M SPORT AUTO
420I M SPORT PRO EDITION AUTO
420I XDRIVE M SPORT AUTO
420I XDRIVE M SPORT PRO ED A
430D M SPORT MHEV AUTO
430D M SPORT PRO ED MHEV A
430D XDRIVE M SPORT MHEV AUTO
430I M SPORT AUTO
430I M SPORT PRO EDITION AUTO
435D GRAN COUPE XDRIVE M SPORT
435D XDRIVE
M440D XDRIVE MHEV AUTO
M440I
M440I XDRIVE MHEV AUTO

Check a specific BMW 4 Series

A model average tells you the pattern. Its own MOT record tells you the car.

Compare within the range

Other BMW models

BMW 3 Series — 80.0% adjusted
BMW 1 Series — 77.6% adjusted
BMW 5 Series — 82.0% adjusted
BMW 2 Series — 82.9% adjusted
BMW X1 — 79.5% adjusted
BMW X3 — 79.5% adjusted
All BMW models

Similar test volumes

Compare against other makes

Audi TT — 81.0% adjusted, ranked 48
Ford Ecosport — 72.4% adjusted, ranked 140
Land Rover Freelander — 72.6% adjusted, ranked 137
Renault Trafic — 62.9% adjusted, ranked 239

Common questions

Is the BMW 4 Series reliable?: On MOT evidence the BMW 4 Series is well above average. It passes 83.2% of tests once age and mileage are accounted for, against a national average of 72.3%. That figure covers 77% of the national age and mileage range, which is enough to quote but not to rank. This measures how often the car meets the MOT standard, not how often it breaks down or what a repair costs.
What is the most common MOT failure on a BMW 4 Series?: The item recorded most often is "A tyre cords visible or damaged", which appears in 18.7% of failed BMW 4 Series tests. Because one failed test can list several items, these shares do not add up to 100%.
What do testers most often warn about on a BMW 4 Series?: The most common advisory is "Tyre tread depth not in accordance with the requirements", noted on 25.0% of all BMW 4 Series tests. An advisory is not a failure: it flags something that will likely need attention before the next test.
What mileage does a BMW 4 Series usually have at its MOT?: The average odometer reading recorded at test is 67,269 miles. This is the mileage across all tested examples of every age, not an annual figure, so treat it as a description of the fleet rather than a target for one car.
Does a BMW 4 Series get harder to pass as it ages?: Yes. At 3 to 5 years old, 88.1% of BMW 4 Series tests pass. By 12 to 14 years, that falls to 77.0%. Nearly every model follows this pattern, which is why comparing raw pass rates between models is misleading unless age is accounted for.
Are most BMW 4 Series models petrol or diesel?: Of the BMW 4 Series cars tested, 56% are diesel, 38% are petrol, 3% are diesel hybrid. Fuel type affects which items tend to fail, particularly emissions and exhaust components.

How this was worked out

Method and limits

Figures come from the DVSA anonymised MOT testing dataset, published under the Open Government Licence. Only class 4 initial tests are counted: retests are excluded so a car appears once, and abandoned tests are excluded entirely. The adjusted rate is directly standardised across twenty-five age and mileage bands and reweighted onto the national distribution, so this model is compared against cars that have lived a similar life rather than against a younger or lighter-used fleet.

An MOT measures whether a car met a legal standard on the day. It is not a breakdown record, a service history or a running-cost estimate, and a pass rate is a property of a fleet rather than a prediction about one car.