1999 · 25 years old at test · Petrol mostly

1999 Porsche 911 MOT pass rate and common faults

1,144 MOT tests in 2024. 80.1% passed first time, compared with 63.3% for all cars the same age.

127Well above average
Passed first time80.1%
Failed or needed repairs19.9%
Typical mileage at test93,000

Most common reasons for failing

Share of all 1,144 tests where this item caused a failure.

  1. Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits2.6%
  2. Rigid brake pipes: excessively corroded2.1%
  3. Tread depth below requirements of 1.6mm1.7%
    66 marked dangerous
  4. Position lamp: not working1.4%
  5. Headlamp aim: projected beam image is obviously incorrect1.3%
  6. Joints: constant velocity boot split or insecure, no longer prevents the ingress of dirt1.3%
  7. Catalyst emissions: carbon monoxide content after 2nd fast idle exceeds manufacturer's specified limits1.0%
  8. Headlamp: not working on dipped beam0.9%
  9. Rear fog lamp: not working0.9%
  10. Wipers: does not clear the windscreen effectively0.9%

Problem areas

Failure items found per 100 tests, by part of the car.

  1. Lights & electrics13.5%
  2. Emissions & leaks6.6%
  3. Brakes6.4%
  4. Tyres3.4%
  5. Suspension3.3%
  6. Visibility (wipers, screen, mirrors)3.2%
  7. Body & chassis2.6%
  8. Steering1.1%

Most common advisories

Not failures yet, but things the tester warned about.

  1. Rigid brake pipes: excessively corroded9.9%
  2. Brake discs: in such a condition that it is seriously weakened9.8%
  3. Engine oil leaks: leaking excessively from engine8.1%
  4. Tread depth below requirements of 1.6mm7.8%
  5. Tyres - condition: has a tear, caused by separation or partial failure of its structure4.5%

What this means if you are buying one

This model year does better than most cars its age, so it is a reasonable used buy on MOT record alone. Before buying, check the area that fails most: catalyst emissions: lambda reading after 2nd fast idle outside specified limits. Then look up the car's own MOT history on GOV.UK with its number plate, and look for repeat advisories.

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Questions

What is the MOT pass rate for a 1999 Porsche 911?

In 2024, 80.1% of 1999 Porsche 911 cars passed their MOT first time, across 1,144 tests. The average for all 25-year-old cars was 63.3%.

What are the most common MOT failures on a 1999 Porsche 911?

The most common failure reasons were catalyst emissions: lambda reading after 2nd fast idle outside specified limits; rigid brake pipes: excessively corroded; tread depth below requirements of 1.6mm. The biggest problem area was lights & electrics.

Is the 1999 Porsche 911 reliable at MOT time?

Its MOT Rank score is 127, which is well above average for a car of its age (100 means exactly average).