Mercedes-Benz E-Class 2004: reliability & common MOT faults

In 2025, 68 in every 100 first MOTs on a 2004 Mercedes-Benz E-Class were passes. Most common reason for a fail: Suspension arm ball joint (front).

Summary

The 2004 Mercedes-Benz E-Class follows the pattern of the model years either side.

At a glance

How 3,206 first tests went in 2025.

Passed first time
68 in every 100
Did not pass first time
32 in every 1001,023 failed first-attempt tests
The typical car
21 yearsabout 133,986 miles
First tests counted
3,206

What failed most often

  1. Suspension arm ball joint (front)20 in every 100 failed tests
  2. Suspension arm ball joint dust cover (front)9 in every 100 failed tests
  3. Handbrake efficiency below minimum (roller test)8 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 2004 Mercedes-Benz E-Class 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.

Suspension

Four faults. The strongest is the other suspension component ball joint (front): 5.2 times as often as on similar cars.

Figures below are measured across the 1,011 of 1,023 failed first attempts (98.8%) 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.

Other suspension component ball joint (front)

Failed on 28 first tests5.2 times as often as similar carsPossible evidence

What it means

Under DVSA's general suspension wording, a ball joint that is excessively worn is Major. One likely to become detached is graded Dangerous.

Suspension mounting area (front)

Failed on 57 first tests3.4 times as often as similar carsLikely evidence

What it means

The load bearing structure within a set distance of a sub-frame, spring or suspension component mounting is a prescribed area. Major applies when its strength or continuity is significantly reduced or it is inadequately repaired. Dangerous applies when it is so weakened that control of the vehicle is likely to be adversely affected.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 43 first tests, 4.3 times as often as on similar cars.

Suspension arm ball joint dust cover (front)

Failed on 91 first tests3.3 times as often as similar carsLikely evidence

What it means

Whether a suspension arm ball joint dust cover still keeps dirt out decides its grade. Severely deteriorated is Minor, while missing, or no longer preventing the ingress of dirt, is Major.

Suspension arm ball joint (front)

Failed on 205 first tests3.0 times as often as similar carsLikely evidence

What it means

A suspension arm ball joint is failed under the general suspension pin, bush or joint wording. Excessively worn is Major, and likely to become detached is graded Dangerous.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 95 first tests, 3.0 times as often as on similar cars.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage. Advisories count notes recorded on failed first tests only.

Tyres

One wear pattern: tyre tread depth (rear), 2.8 times as often as on similar cars.

Tyre tread depth (rear)

Failed on 72 first tests2.8 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.

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

Lamps and electrical

One fault: side repeater indicators, 2.6 times as often as on similar cars.

Side repeater indicators

Failed on 48 first tests2.6 times as often as similar carsPossible evidence

What it means

Sequential or dynamic direction indicators are not a reason to fail. Where a side repeater is required, it is allowed to be part of the front direction indicator if it has a marked wraparound lens, or an amber light coming through the front lens when viewed from a set distance to the side of the rear bumper. A lens defect with no effect on the emitted light is Minor, and one that adversely affects the light is Major.

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. Advisories for the faults above are shown with those faults.

Wheel bearings (front)

Noted on 105 first tests4.7 times as often as similar carsElevated evidence

Rigid brake pipes (front)

Noted on 164 first tests2.3 times as often as similar carsElevated evidence

Brake pads (rear)

Noted on 80 first tests2.3 times as often as similar carsWear pattern

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
68in every 100
Passed on the first test.
Fixed at the station
5in every 100
Failed, then fixed at the test station the same day.
Failed
27in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 68.1% of 3,206 first tests (2025): only cars that passed first time count. Official-style pass 72.7%: cars fixed at the test station also count as a pass. The 5 fixed and the 27 not fixed make the 32 in every 100 that did not pass first time.

Petrol and diesel

First testsTypical mileagePassed first time, as testedPassed first time, same mileage
Diesel2,227144,783 miles6767
Petrol974111,265 miles7271

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.

40608010020002004201020152020Older carsNewer cars
4060801002000200420102020Newer 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, 67 in every 100 passed first time.

YearPassed first timeFirst tests
199870 in every 100422
199971 in every 100369
200073 in every 100408
200165 in every 100554
200267 in every 100760
200368 in every 1002,313
2004 This car68 in every 1003,206
200566 in every 1003,241
200668 in every 1002,945
200771 in every 1004,547
200870 in every 1003,705
200970 in every 1005,810
201069 in every 1009,946
201169 in every 10011,790
201268 in every 10012,962
201371 in every 10016,872
201475 in every 10018,459
201577 in every 10019,522
201681 in every 10018,607
201783 in every 10019,815
201883 in every 10018,699
201985 in every 10018,126
202085 in every 1008,987
202187 in every 1005,439
202287 in every 1002,823

If you are buying one

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

Mileage matters most on a 2004 E-Class.

Of 2004 E-Class vehicles with under 94,000 miles, 75 in every 100 passed their 2025 MOT first time. With 181,000 miles or more, 66 in every 100 did.

Under 94,000638 tests
75
94,000–120,000628 tests
68
120,000–147,000 Typical car635 tests
68
147,000–181,000636 tests
65
181,000 and over642 tests
66

Petrol or diesel?

Typical mileagePassed first time,
as tested
Passed first time,
same mileage
Diesel144,783 miles6767
Petrol111,265 miles7271

Figures are in every 100 first tests. Petrol cars look better on the raw figures only because diesel cars have done more miles (typically 144,783 against 111,265). 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 94,000120,000–147,000181,000 and over
Suspension arm ball joint (front)5.26.55.6
Suspension arm ball joint dust cover (front)2.52.03.0
Handbrake efficiency below minimum (roller test)1.41.64.4
Headlight aim1.91.73.1
Tyre tread depth (rear)2.41.73.0

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


When a car fails

26in every 100

of failed cars had one item to fix.

50in every 100

of failed cars had three or more items to fix.

8in 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 2004 Mercedes-Benz E-Class follows the pattern of the model years either side. Its main cause of failure was Suspension arm ball joint (front), about 20 in every 100 failed tests. In 2025, 68.1% of 3,206 first MOTs on the 2004 Mercedes-Benz E-Class passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 72.7%. Among 1,023 failed first-attempt MOT tests (test year 2025), Other suspension component ball joint (front) appears more often than on similar cars (2.8% of those tests; 28 observed failures; about 5.2× 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 2004 Mercedes-Benz E-Class at the first attempt were Suspension arm ball joint (front) (20.3%), Suspension arm ball joint dust cover (front) (9.0%) and Handbrake efficiency below minimum (roller test) (8.1%), 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: Other suspension component ball joint (front) (2.8% of those tests; 28 observed failures; about 5.2× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Other suspension component ball joint (front) shows up more often than on similar cars (2.8% of those tests; 28 observed failures; about 5.2× 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 2004 Mercedes-Benz E-Class include Other suspension component ball joint (front), Suspension mounting area (front), Suspension arm ball joint dust cover (front). 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 2004 Mercedes-Benz E-Class (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.

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