Porsche 911 - 2021
20.5 faults per 100 tests
Year average for all cars of 2021 is 80.0 faults per 100 tests
Dataset: MOT tests in Great Britain (period: 2024-01-01 to 2025-09-10) for Porsche 911, model year 2021.
Sample size: 2,337 cars, 5,879 tests and 1,208 recorded faults.
0%
Less faults compared to the average car of same model year
Less faults compared to the average car of same model year
Quick summary
Total: 2,337 cars
The 2021 Porsche 911 shows an overall defect rate of 21 defects per 100 vehicles, significantly lower than the average of 79 defects per 100 for cars of the same year, making it 74% better than average. This model particularly excels in categories such as brakes, steering, and visibility, with defect rates far below the average in these areas. While tyre wear is noted, it is not a standout issue for this model; instead, the 911's performance is commendable across various critical categories, indicating a robust build quality. Additionally, the data suggests that higher mileage vehicles generally report more defects, as expected, but the 911 maintains a relatively low defect rate even in lower mileage brackets.
Cars by mileage segment
Total: 2,337 cars
Categories
Brakes
▲ 95.5% better
1.8 faults / 100 tests
Year avg: 40.0 / 100 tests
- Brake disc or drum: insecure, fractured or otherwise likely to fail
- Excessive fluctuation in brake effort through each wheel revolution
- Brake pipe damaged or excessively corroded
- Brake disc or drum: significantly and obviously worn
- Brake lining or pad: worn below 1.5mm
Steering
▲ 100.0% better
0.0 faults / 100 tests
Year avg: 0.7 / 100 tests
- A steering ball joint: with excessive wear or free play
Visibility
▲ 78.6% better
3.1 faults / 100 tests
Year avg: 14.5 / 100 tests
- Windscreen or window damaged or seriously discoloured: but not adversely affecting driver’s view
- Wiper blade: missing or obviously not clearing the windscreen
- Wiper blade: defective
- Windscreen or window excessively tinted: but not adversely affecting driver’s view
- Windscreen washers not working or not providing sufficient fluid to clear the windscreen
Lights & Electrics
▲ 85.7% better
1.6 faults / 100 tests
Year avg: 11.2 / 100 tests
- A direction indicator: lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
- A lamp: not securely attached
- The aim of a headlamp is not within limits laid down in the requirements
- The aim of a headlamp is not within limits laid down in the requirements
- A lamp: likely to become detached
Wheels & Suspension
▲ 61.9% better
33.3 faults / 100 tests
Year avg: 87.3 / 100 tests
- A tyre: with a lump, bulge or tear … or with cords exposed or damaged
- A tyre: with a cut in excess of the requirements deep enough to reach the ply or cords
- Tyre tread depth not in accordance with the requirements
- A tyre: with a cut in excess of the requirements deep enough to reach the ply or cords
- Tyre tread depth not in accordance with the requirements
Body/Structure
▲ 95.2% better
0.1 faults / 100 tests
Year avg: 2.1 / 100 tests
- A transmission shaft constant velocity joint boot: missing, split, insecure or no longer prevents the ingress of dirt
- A driver’s seat: fore and aft adjustment mechanism not working as intended
Equipment
▲ 93.3% better
0.1 faults / 100 tests
Year avg: 1.5 / 100 tests
- A seat belt: or flexible stalk damaged
Other
▲ 59.3% better
1.1 faults / 100 tests
Year avg: 2.7 / 100 tests
- Exhaust noise levels in excess of those permitted
- Fluid: leaking excessively and likely to harm the environment or to pose a safety risk to other road users
- Fluid: leaking excessively and likely to harm the environment or to pose a safety risk to other road users
- Lambda coefficient outside the default limits or the range specified by the manufacturer
- Engine MIL inoperative or indicating a malfunction
Fault rate by mileage segment
Model
Year average
* Metric: faults per 100 tests.
Most common faults (Top 10)
Tyre tread depth not in accordance with the requirements
ADVISORY
Occurrences: 485
A tyre: with a lump, bulge or tear … or with cords exposed or damaged
ADVISORY
Occurrences: 249
A tyre: with a cut in excess of the requirements deep enough to reach the ply or cords
ADVISORY
Occurrences: 82
Windscreen or window damaged or seriously discoloured: but not adversely affecting driver’s view
MINOR
Occurrences: 55
A tyre: with a cut in excess of the requirements deep enough to reach the ply or cords
FAIL
Occurrences: 45
The aim of a headlamp is not within limits laid down in the requirements
PRS
Occurrences: 39
Tyre tread depth not in accordance with the requirements
FAIL
Occurrences: 39
Brake disc or drum: insecure, fractured or otherwise likely to fail
ADVISORY
Occurrences: 37
A tyre: with a lump, bulge or tear … or with cords exposed or damaged
FAIL
Occurrences: 23
Windscreen or window excessively tinted: but not adversely affecting driver’s view
MINOR
Occurrences: 19
Serious faults (Top 10)
A tyre: with a cut in excess of the requirements deep enough to reach the ply or cords
FAIL
Occurrences: 45
Tyre tread depth not in accordance with the requirements
FAIL
Occurrences: 39
A tyre: with a lump, bulge or tear … or with cords exposed or damaged
FAIL
Occurrences: 23
A shock absorber damaged … or showing signs of severe leakage
FAIL
Occurrences: 6
Windscreen washers not working or not providing sufficient fluid to clear the windscreen
FAIL
Occurrences: 5
Lambda coefficient outside the default limits or the range specified by the manufacturer
FAIL
Occurrences: 4
Fluid: leaking excessively and likely to harm the environment or to pose a safety risk to other road users
FAIL
Occurrences: 3
Tyre pressure monitoring system malfunctioning or obviously not working
FAIL
Occurrences: 3
A direction indicator: lamp missing, inoperative or in the case of a multiple light source more than 1/2 not functioning
FAIL
Occurrences: 2
A transmission shaft constant velocity joint boot: missing, split, insecure or no longer prevents the ingress of dirt
FAIL
Occurrences: 2