What 2,209 MOT tests in 2025 say about buying one used — and, just as important, what they cannot tell you.
Judged against every other electric car of the same age — aged 3 to 5 — this one passes at 85.5% against 86.3% for the electric fleet. That is close enough to call it a wash. Neither the problem nor the answer: judge the individual car, not the badge. Against the petrol and hybrid versions of the same nameplate it is a wash at matched ages: 85.5% versus 85.7%. And whatever the MOT record says, it tells you nothing about the battery — no record does. Only a physical test measures that.
Battery warranty terms per model year — years, mileage cap, capacity-retention threshold, and whether it transfers to a second owner — have to be traced to the manufacturer’s own published documentation, row by row, and dated. That table has not been built.
We will not sell you a battery state-of-health figure we have not measured. Ours would be a guess, so we are not selling it. Where a physical test is worth its roughly £100, we will say so plainly.
By registration year, because that is how a buyer thinks about it. Mileage matters more on an electric car than a petrol one: it is both the main thing that ages a battery and the cap that ends the warranty.
| Registration year | Age in 2025 | Tests | Bottom quarter | Median | Top quarter |
|---|---|---|---|---|---|
| 2020 | 5 | 621 | 11,250 | 16,250 | 23,750 |
| 2021 | 4 | 610 | 8,750 | 13,750 | 21,250 |
| 2022 | 3 | 594 | 6,250 | 11,250 | 16,250 |
A 2021 ForFour showing about 13,750 miles is dead average. One showing 21,250 or more is in the top quarter and has been worked harder than most — it will reach any mileage-capped warranty limit years sooner than the odometer alone suggests. Working out which cap expires first, for one specific registration, is what the check does.
| Age | Pass rate | Tests |
|---|---|---|
| 3 yrs | 87.7% | 1,848 |
| 4 yrs | 83.7% | 1,400 |
| 5 yrs | 83.7% | 937 |
This nameplate is sold with petrol and electric versions. Everyone else quotes the blended figure for both together, which is mostly a statement about age — the electric ones are all recent cars. Weighted so both sides carry the same age mix, ages 3 to 5:
| Version | Pass rate, age-matched | Tests |
|---|---|---|
| ForFour electric | 85.5% | 4,185 |
| ForFour, all fuel types | 85.7% | — |
The un-weighted comparison would read 72.7% for the nameplate overall. We do not publish that number against an electric figure, because the gap it shows is mostly the age difference between the two groups rather than anything about the cars.
The fall between 3 and 4 years is the one to notice. The pass rate drops from 87.7% to 83.7% in a single year of age — 4.0 points, the steepest step anywhere on the chart above. That is 1,848 tests against 1,400, so it is not a small-sample artefact.
Read it as a maintenance cliff rather than a design fault: it is the age at which the consumable parts on this model come due together. If you are looking at one approaching 4 years old, budget for it, or use it to negotiate.
Advisory and failure items for this model are not published yet. The item-level data needs the DVSA test-item files joined to this model’s electric tests, and the figures that exist elsewhere blend petrol and electric versions of this nameplate together — which would be misleading here.
This page describes the model. The free check describes the car in front of you.
The check costs nothing. A free account is needed so results can be saved and cars compared side by side — no card, no charge. Paid reports are extra and every price is on the page before you type a registration, never after.