2025 MOT results
Mercedes-Benz Viano common problems
The most common reason a Mercedes-Benz Viano fails its MOT is a weak handbrake, on 10.4% of its 1,720 failed tests in 2025. Against other cars of the same age, 3 faults stand out: a weak handbrake at 7.2% of failures against 1.3% expected; an indicator repeater out at 8.8% of failures against 1.7% expected; the airbag light on at 7.6% of failures against 2.0% expected.
- Tests in 2025 5,004 Cars aged three and over
- Failed first time 34.4% 1,720 tests
- Found a dangerous defect 9.2% Unsafe to drive away
- Ended with an advisory 61.2% A problem to watch, not a failure
What fails a Mercedes-Benz Viano MOT
Each bar is the share of failed Mercedes-Benz Viano tests with that defect. Where we can compare it with cars of the same registration years, the marker shows what an average car of those ages records (12 of the 12 items below).
Most common reasons for failure
A test can fail for more than one defect, so shares add up to more than 100%.
| Defect | Share of failed tests |
|---|---|
| Parking brake efficiency below requirements Brakes | 10.4% |
| Position lamp: not working Lamps, reflectors and electrical equipment | 9.9% |
| Side repeaters: not working Lamps, reflectors and electrical equipment | 8.8% |
| Stop lamp: not working Lamps, reflectors and electrical equipment | 8.1% |
| SRS malfunction indicator lamp: warning lamp indicates a fault Seat belts and supplementary restraint systems | 7.6% |
| Parking brake efficiency less than 50% of the required value Brakes | 7.2% |
| Malfunction indicator lamp: inoperative or indicates a malfunction Noise, emissions and leaks | 6.8% |
| Tyres: tread depth below requirements of 1.6mm Tyres | 5.6% |
| Headlamp: not working on dipped beam Lamps, reflectors and electrical equipment | 5.3% |
| Headlamp aim: too low Lamps, reflectors and electrical equipment | 5.2% |
| Tyres: ply or cords exposed Tyres | 5.2% |
| Headlamp aim: projected beam image is obviously incorrect Lamps, reflectors and electrical equipment | 4.9% |
Source:DVSA,UK Motoring analysis 2025 Updated
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Weak handbrake
10.4% of failures 5.1% expected 2 times as often
The handbrake cannot hold the car to the efficiency the test requires, usually from a stretched cable or seized rear callipers.
On a hill, the handbrake should hold the car with a couple of clicks left in the lever.
-
Sidelight out
9.9% of failures 11.7% expected somewhat less often
A sidelight, also called a position lamp, not working. It marks the width of the car at night.
Walk round the car with the lights on and the hazards going; these are the cheapest failures to avoid.
-
Indicator repeater out
8.8% of failures 1.7% expected 5.2 times as often
The small indicator lamp in the wing or mirror not working.
Walk round the car with the lights on and the hazards going; these are the cheapest failures to avoid.
-
Brake light out
8.1% of failures 8.2% expected about as expected
A brake light not working, from a bulb, a poor earth, or the switch on the pedal.
Reverse up to a wall or window at dusk and press the pedal to see all three lamps light.
-
Airbag light on
7.6% of failures 2.0% expected 3.8 times as often
The airbag warning light shows a fault in the restraint system.
Common causes are a seat belt buckle sensor, or a wiring loom under a front seat.
-
Weak handbrake
7.2% of failures 1.3% expected 5.5 times as often
The handbrake cannot hold the car to the efficiency the test requires, usually from a stretched cable or seized rear callipers.
On a hill, the handbrake should hold the car with a couple of clicks left in the lever.
Which parts of the car fail
Lamps, reflectors and electrical equipment is the area that most often fails a Mercedes-Benz Viano, on 50.6% of failed tests. The widest gap against cars of the same registration years is brakes, on 33.1% against 24.0% expected.
Failure categories
DVSA's own sections of the test. The marker is what cars of the same registration years record.
| Defect category | Share of failed tests |
|---|---|
| Lamps, reflectors and electrical equipment | 50.6% |
| Brakes | 33.1% |
| Suspension | 28.0% |
| Tyres | 15.6% |
| Body, chassis, structure | 13.8% |
| Visibility | 13.3% |
| Noise, emissions and leaks | 11.8% |
| Seat belts and supplementary restraint systems | 10.1% |
Source:DVSA,UK Motoring analysis 2025 Updated
What testers warn about
61.2% of Mercedes-Benz Viano tests ended with at least one advisory: a fault the tester found that did not fail the test. On Mercedes-Benz Vianos, these are the items to ask about on a car you are viewing, because they are what the last tester expected to go next.
Most common advisories
Share of all tests, passes included.
| Advisory | Share of tests |
|---|---|
| Tread depth: worn close to legal limit or worn on edge Tyres | 21.5% |
| Engine oil leak, but not excessive Noise, emissions and leaks | 10.6% |
| Rigid brake pipes: corroded, covered in grease or other material Brakes | 9.6% |
| Brake discs: worn, pitted or scored, but not seriously weakened Brakes | 8.6% |
| Exhaust system: mounting defective Body, chassis, structure | 5.1% |
| Brake pads: wearing thin Brakes | 4.6% |
| Play in steering rack inner joint(s) Non-component advisories | 4.5% |
| Suspension arms: pin or bush worn but not resulting in excessive movement Suspension | 4.2% |
| Tyres: slightly damaged or cracking or perishing Tyres | 4.0% |
| Individual direction indicators: slightly discoloured Lamps, reflectors and electrical equipment | 3.9% |
| Linkage pins and bushes: pin or bush worn but not resulting in excessive movement Suspension | 3.2% |
| Brake discs: worn, but not excessively Brakes | 3.2% |
Source:DVSA,UK Motoring analysis 2025 Updated
Mercedes-Benz Viano problems: common questions
What is the most common problem with a Mercedes-Benz Viano?
Of the faults that fail an MOT, “Parking brake efficiency below requirements” is the most common: it appears on 10.4% of failed Mercedes-Benz Viano tests. Across categories, lamps, reflectors and electrical equipment is the area that most often fails one, on 50.6% of failed tests.
How often does a Mercedes-Benz Viano fail its MOT?
34.4% of Mercedes-Benz Viano tests in 2025 were not passed first time, from 5,004 tests of cars aged three and over. Allowing for the age and mileage of the cars tested, that gives it a UK Motoring Reliability Score of 56 out of 100, where 50 is as expected.
Does anything fail more often on a Mercedes-Benz Viano than on other cars?
Yes. “Parking brake efficiency less than 50% of the required value” appears on 7.2% of its failures against 1.3% for cars of the same age, and “Side repeaters: not working” appears on 8.8% of its failures against 1.7% for cars of the same age. Where an item is missing from the national figures for a year, we use the smallest share those figures show, so the comparison never overstates the difference.
Are these the same as breakdowns or known faults?
No. These are the items a tester recorded at the MOT, which covers condition and safety: lamps, brakes, tyres, suspension, corrosion and emissions. A gearbox that is unpleasant, an infotainment screen that has died, or a car that will not start on a cold morning are not part of the test, so they are not in these figures.
Where do the figures come from?
Every normal MOT test of a Mercedes-Benz Viano aged three and over in Great Britain in 2025, from DVSA's anonymised MOT results. Retests are excluded, and the same fault on more than one wheel counts once.
Data stories to read next
Data sources and methodology
| Figures | Source | Period | Records | Updated |
|---|---|---|---|---|
| MOT defects and advisories | Anonymised MOT tests and results Driver and Vehicle Standards Agency Derived statistics UK Motoring | 2025 | 5,004 MOT tests | 19 September 2026 |
- Shares for defects are of failed tests; shares for advisories are of all tests. A test can carry several defects, so shares add to more than 100%.
- The expected share is what an average car of the same registration years records, weighted by where this model’s failures fall. Where an item is outside the national figures for a year, the smallest share those figures show is used in its place, which is an upper bound, so the comparison never overstates a model’s problems. No expectation is published where less than 80% of the model’s failures can be compared.
- Great Britain only: DVSA does not run MOT testing in Northern Ireland. Cars under three years old are not tested.
- The descriptions of what each part does are general and the same on every model. Every figure comes from the MOT data.
Contains public sector information licensed under the Open Government Licence v3.0.