Ford Mustang 2020: reliability & common MOT faults

At a glance

How 1,015 first tests went in 2025.

Passed first time: 87 in every 100
Did not pass first time: 13 in every 100136 failed first-attempt tests
The typical car: 5 yearsabout 21,003 miles
First tests counted: 1,015

How we count this. Data: UK MOT open data, 2025. Only Class 4 cars on their first MOT of the year are counted. A car that fails and is fixed at the test station still counts as a fail in the first-attempt rate. These are raw results, not adjusted for age, mileage, or peer mix. The MOT does not test engine or gearbox internals.

Note:

These are patterns across 2020 Ford Mustang vehicles in 2025, not a prediction that any one car will have them. Faults are grouped by part of the car. They come from MOT defect codes, not manufacturer bulletins, recalls or a diagnosis of any one car.

Brakes

One fault: handbrake efficiency below minimum (roller test), 30 times as often as on similar cars.

Figures below are measured across the 136 failed first attempts in 2025 that had a mileage recorded, which allows a like-for-like comparison.

We only list faults with at least 20 failures and a rate of about 2.0 times that of similar cars, which keeps one-off results out of the list.

Handbrake efficiency below minimum (roller test)

Failed on 39 first tests30 times as often as similar carsLikely evidence

What it means

A parking brake with efficiency below the minimum requirement is Major, and graded Dangerous where efficiency is less than half of the required value. On a roller brake tester, the requirement counts as met if more than half of the wheels of a brake system lock. The check applies only to vehicles whose parking brake was not already tested as the secondary brake.

Data: UK MOT open data, 2025. Compared with cars of the same age and mileage.

MOT pass rates

How first tests ended, and how the pass rates are counted.

Passed first time: 87in every 100; Passed on the first test.
Fixed at the station: 1in every 100; Failed, then fixed at the test station the same day.
Failed: 12in every 100; Did not pass, and were not fixed at the test station.

First-attempt pass 86.6% of 1,015 first tests (2025): only cars that passed first time count. Official-style pass 88.5%: cars fixed at the test station also count as a pass. The 1 fixed and the 12 not fixed make the 13 in every 100 that did not pass first time.

Same model, other years

Passed first time in every 100, all tested in 2025.

Newer cars are younger, so look for a jump rather than the climb. A year earlier (2024), when these cars were a year younger, 86 in every 100 passed first time.

Year	Passed first time	First tests
2015	85 in every 100	318
2016	81 in every 100	2,384
2017	82 in every 100	1,781
2018	83 in every 100	1,982
2019	85 in every 100	1,145
2020 This car	87 in every 100	1,015
2021	90 in every 100	3,007
2022	89 in every 100	4,819

FAQs

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

Is the 2020 Ford Mustang reliable?

The 2020 Ford Mustang follows the pattern of the model years either side. In 2025, 86.6% of 1,015 first MOTs on the 2020 Ford Mustang passed first time (PRS: items fixed at the station the same day, counted as a fail). The official-style rate including PRS is 88.5%. Among 136 failed first-attempt MOT tests (test year 2025), Handbrake efficiency below minimum (roller test) appears more often than on similar cars (28.7% of those tests; 39 observed failures; about 30× more often than similar cars). There is no single reliability score here; this is a pre-purchase checklist built from DVSA open data, not a guarantee for any individual car.

What common MOT faults stand out on the Ford Mustang 2020?

Among failed first-attempt tests we highlight patterns that appear more often than on similar cars. Top example: Handbrake efficiency below minimum (roller test) (28.7% of those tests; 39 observed failures; about 30× more often than similar cars). These are statistical signals, not a diagnosis of any individual car.

Why does Handbrake efficiency below minimum (roller test) stand out?

Handbrake efficiency below minimum (roller test) shows up more often than on similar cars (28.7% of those tests; 39 observed failures; about 30× more often than similar cars). That does not prove a design fault. Age, mileage, and how the car was used still matter. Treat it as a pre-purchase checkpoint, not a manufacturer service bulletin.

What are common problems with the 2020 Ford Mustang?

Common MOT problem areas for the 2020 Ford Mustang include Handbrake efficiency below minimum (roller test). These are the faults that stand out compared with similar cars, not a complete list of what can go wrong on any individual car.

What does this Ford Mustang 2020 MOT report cover?

This page highlights MOT failure patterns for the 2020 Ford Mustang (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.

Does this include engine and gearbox problems?

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.

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.
If the data for a car is too thin to say anything useful, we say so rather than guess.

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