Mercedes-Benz S-Class: MOT pass rate and reliability data

The Mercedes-Benz S-Class passes its MOT first time more often than the average UK car, by 7.8 percentage points. These figures come from the DVSA's full year of anonymised MOT results, covering 25,806 individual Mercedes-Benz S-Class tests. Nothing here is an estimate or a survey.

The numbers

First-time pass rate84.5%
UK national average76.7%
Difference+7.8 points
Tests analysed25,806
Average mileage at test92,448 miles
Average year of manufacture2012
Reliability rank1,270 of 2,005 models

What this means if you are buying one

A 84.5% first-time pass rate means roughly 16 in every 100 Mercedes-Benz S-Class presented for MOT fail on the first attempt. That is better than average, so a well-kept example is a reasonably safe used buy. The average Mercedes-Benz S-Class tested had covered 92,448 miles and was built around 2012.

What this means at salvage auction

Pass rate is a proxy for what a car costs to keep on the road. The Mercedes-Benz S-Class sits 7.8 points above the national average, ranked 1,270 of 2,005 models. On one bought as repairable salvage, the mechanical side is less likely to spring surprises, so your repair estimate should hold up reasonably well.

Before you bid: run the lot through the analyzer, check the car's own record, check the mileage, decode the VIN, and if it carries a marker use the write-off value calculator. Or compare it against another model.

Looking at a specific Mercedes-Benz S-Class rather than the model in general? The free check covers its MOT and mileage history, and the full HPI report confirms the insurance write-off category, outstanding finance and whether it is recorded stolen, from licensed data for 5 credits. Already own one that has been damaged? Work out whether fixing it beats selling it with the repair or scrap calculator, and see the median recorded closing bid for a damaged Mercedes-Benz S-Class: £450 at UK salvage auction, from 7 ended listings, not independently confirmed sales.

Most common MOT failures on a Mercedes-Benz S-Class

  1. Smoke opacity levels exceed the manufacturer's specified limit, 0.6% of tests (2.07x the national rate for this defect)
  2. Warning device shows system malfunction, 0.6% of tests (1.34x the national rate for this defect)
  3. A suspension pin, bush or joint excessively worn, 4.9% of tests
  4. Tyre tread depth not in accordance with the requirements, 3.2% of tests
  5. A tyre seriously damaged, 2.2% of tests
  6. A tyre cords visible or damaged, 1.5% of tests
  7. Engine MIL illuminated indicating a malfunction, 1.3% of tests
  8. Brake pipe damaged or excessively corroded, 1.2% of tests
  9. Windscreen washers not working or not providing sufficient fluid to clear the windscreen, 1% of tests
  10. A suspension joint dust cover missing or no longer prevents the ingress of dirt etc, 0.9% of tests

From 25,787 DVSA-tracked Mercedes-Benz S-Class tests, 2024. DVSA testers marked 6.23% of these flagged Mercedes-Benz S-Class defects as "dangerous", meaning the tester judged the car unsafe to drive away, against 5.11% nationally.

Most common MOT advisories on a Mercedes-Benz S-Class

An advisory doesn't fail the car - the tester flags it as worth watching, but it still passes. A different list from the failures above: what testers are noting on a Mercedes-Benz S-Class before it actually fails on it.

  1. A wheel bearing with excessive play, 3.7% of tests (5.76x the national rate for this advisory)
  2. A flexible brake hose excessively damaged, deteriorated, chafed, twisted or stretched, 1.3% of tests (2.31x the national rate for this advisory)
  3. Brake pipe damaged or excessively corroded, 10.4% of tests (1.69x the national rate for this advisory), also fails
  4. Brake disc or drum significantly and obviously worn, 4.2% of tests (1.31x the national rate for this advisory)
  5. Tyre tread depth not in accordance with the requirements, 26.6% of tests, also fails
  6. A suspension pin, bush or joint excessively worn, 11% of tests, also fails
  7. Brake disc or drum excessively weakened, insecure or fractured, 9.7% of tests
  8. a brake lining or pad worn below 1.5mm, 7.2% of tests
  9. A tyre seriously damaged, 6.9% of tests, also fails
  10. Fluid leaking excessively and likely to harm the environment or to pose a safety risk to other road users, 5.6% of tests

From 25,787 DVSA-tracked Mercedes-Benz S-Class tests, 2024.

Mercedes-Benz S-Class pass rate by model year

From its 2001 to its 2019 model year, the Mercedes-Benz S-Class's first-time pass rate has risen 19.7 points, from 72.6% to 92.3%, the usual pattern: a newer model year is a younger car today, so it fails less. First-time pass rate for each Mercedes-Benz S-Class year:

Mercedes-Benz S-Class by fuel type

The Mercedes-Benz S-Class's two most-tested fuel types split by 0.4 points: diesel passes first time 85.2% of the time (17,692 tests) against 84.8% for petrol (6,835 tests).

Other Mercedes-Benz models

Models with a similar pass rate

If this car is a salvage or write-off

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Mercedes-Benz S-Class MOT pass rate badge: 84.5%

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Mercedes-Benz S-Class most common MOT failure: Smoke opacity levels exceed the manufacturer's specified limit (0.6% of tests)

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All 2,005 models ranked by MOT pass rate