Model Reports 8 min read Updated 13 Jul 2026

Porsche 911 2017: reliability & common MOT faults

Common MOT faults and reliability patterns for the 2017 Porsche 911, based on UK DVSA open data for tests in 2025.

Sample

114 failed first-attempt tests · 1,786 first tests (test year 2025)

Wear patterns

Usage and mileage effects that often track road use rather than model design.

These patterns look like wear or usage effects rather than model-specific design faults. Tyres, brake friction material, and alignment-related defects often track mileage and road use.

# Pattern Location Failures vs similar cars Share of fails Confidence
1 Tyres — Condition (rear)
Tyres > Condition
 Rear 31 ×2.9 27.2% Wear
Note: These patterns are not treated as a model design fault in our common-faults ranking.

Advisories

Notes recorded at the test that appear more often than on similar cars.

Advisory notes recorded on failed first-attempt tests that appear more often than on similar cars.

# Advisory pattern Location Notes vs similar cars Share Confidence
1 Tread depth (rear)
Tyres > Tread depth
 Rear 20 ×3.8 17.5% Wear
Note: Advisories are not a fail rate — they flag issues noted at the test, often before they become failures.

FAQs

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

We do not show a single reliability score for the 2017 Porsche 911 on this page. Among 114 failed first-attempt MOT tests (test year 2025), we highlight MOT failure patterns that show up more often than on cars of a similar age and mileage when the sample is large enough to trust. Treat this as a pre-purchase checklist from DVSA open data — not a guarantee for 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 2017 Porsche 911 (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.
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.
We count how often each MOT defect pattern appears among failed first-attempt tests for this model year, then compare that with similar cars. 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. A higher multiple means the pattern shows up more often than expected for similar car…
No. Common faults are inferred from MOT defect statistics, not manufacturer technical service bulletins or safety recalls. An elevated pattern is a statistical signal versus similar cars — useful as a pre-purchase check point, not proof of a design defect on any individual car.
Often not. Tyre, brake friction, and aim/alignment patterns frequently track wear and usage. We list them separately so they are not treated as model design faults in the common faults ranking.

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.
  • We never invent pass rates, star scores, or ranks when those data marts are missing.

Contains public sector information licensed under the Open Government Licence v3.0.

Most reliable Porsche models

See brand-wide MOT rankings and year guidance for Porsche (separate from this model-year report).