Model Reports 4 min read Updated 18 Oct 2026

Mercedes-Benz ML 2009: reliability & common MOT faults

In 2025, 67 in every 100 first MOTs on a 2009 Mercedes-Benz ML were passes. Most common reason for a fail: Side repeater indicators.

Summary

The 2009 Mercedes-Benz ML follows the pattern of the model years either side.

At a glance

How 1,700 first tests went in 2025.

Passed first time
67 in every 100
Did not pass first time
33 in every 100569 failed first-attempt tests
The typical car
16 yearsabout 123,673 miles
First tests counted
1,700

What failed most often

  1. Side repeater indicators16 in every 100 failed tests
  2. Coil spring (rear)13 in every 100 failed tests
  3. Individual sidelight or tail light (front)11 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 2009 Mercedes-Benz ML vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Brakes

Two faults. The strongest is the handbrake efficiency below minimum (decelerometer test): 17 times as often as on similar cars.

Figures below are measured across the 568 of 569 failed first attempts (99.8%) 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.

Handbrake efficiency below minimum (decelerometer test)

Failed on 30 first tests17 times as often as similar carsLikely evidence

What it means

A parking brake with efficiency below the minimum requirement is graded Major, and efficiency less than half of the required value is graded Dangerous. This check applies only to vehicles whose parking brake has not already been tested as the secondary brake.

Rigid brake pipes (rear)

Failed on 26 first tests2.6 times as often as similar carsPossible evidence

What it means

Chafing, corrosion or damage to a rigid brake pipe justifies rejection once its wall thickness is reduced by a set amount, although DVSA accepts this is not easy to determine. If a tester is not sure, the benefit of the doubt applies. A leaking pipe or connection is graded Dangerous on a hydraulic system and Major on an air system.

Also noted as an advisory

Testers also noted it as an advisory, worn but not yet failing, on 67 first tests, 2.5 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.

Lamps and electrical

One fault: side repeater indicators, 9.2 times as often as on similar cars.

Side repeater indicators

Failed on 91 first tests9.2 times as often as similar carsLikely 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.

Suspension

One fault: coil spring (rear), 3.1 times as often as on similar cars.

Coil spring (rear)

Failed on 71 first tests3.1 times as often as similar carsLikely evidence

What it means

A missing bump stop rubber is not a reason to fail a coil spring. When the vehicle is jacked and lowered, a spring that does not correctly locate as the suspension returns to its normal running position is rejected as insecurely attached. A missing spring is Major, and graded Dangerous where directional control is affected.

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

Noise, emissions and leaks

One fault: diesel emissions test (compression-ignition rules for vehicles from 01/07/2008), 2.4 times as often as on similar cars.

Diesel emissions test (compression-ignition rules for vehicles from 01/07/2008)

Failed on 34 first tests2.4 times as often as similar carsPossible evidence

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.

Rigid brake pipes (front)

Noted on 55 first tests3.6 times as often as similar carsElevated evidence

Engine oil leaks (front)

Noted on 153 first tests2.1 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
67in every 100
Passed on the first test.
Fixed at the station
7in every 100
Failed, then fixed at the test station the same day.
Failed
26in every 100
Did not pass, and were not fixed at the test station.

First-attempt pass 66.5% of 1,700 first tests (2025): only cars that passed first time count. Official-style pass 73.5%: cars fixed at the test station also count as a pass. The 7 fixed and the 26 not fixed make the 33 in every 100 that did not pass first time.

Same model, other years

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

406080100200520092015Older carsNewer cars
4060801002009Older carsNewer 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, 65 in every 100 passed first time.

YearPassed first timeFirst tests
200156 in every 100348
200259 in every 100619
200359 in every 100698
200457 in every 100937
200559 in every 100724
200667 in every 1001,315
200767 in every 1001,649
200867 in every 1001,811
2009 This car67 in every 1001,700
201068 in every 1002,334
201170 in every 1002,327
201276 in every 1002,402
201380 in every 1003,959
201480 in every 1003,654
201581 in every 1003,031

FAQs

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

The 2009 Mercedes-Benz ML follows the pattern of the model years either side. Its main cause of failure was Side repeater indicators, about 16 in every 100 failed tests. In 2025, 66.5% of 1,700 first MOTs on the 2009 Mercedes-Benz ML passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 73.5%. Among 569 failed first-attempt MOT tests (test year 2025), Handbrake efficiency below minimum (decelerometer test) appears more often than on similar cars (5.3% of those tests; 30 observed failures; about 17× 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 2009 Mercedes-Benz ML at the first attempt were Side repeater indicators (16.0%), Coil spring (rear) (12.5%) and Individual sidelight or tail light (front) (11.3%), 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: Handbrake efficiency below minimum (decelerometer test) (5.3% of those tests; 30 observed failures; about 17× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.
Handbrake efficiency below minimum (decelerometer test) shows up more often than on similar cars (5.3% of those tests; 30 observed failures; about 17× 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 2009 Mercedes-Benz ML include Handbrake efficiency below minimum (decelerometer test), Side repeater indicators, Coil spring (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 2009 Mercedes-Benz ML (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