All generations and engines together · 24,254 MOT tests in the 2025 data · typical mileage at age 7: 54k
Computed from DVSA MOT results, all of Great Britain, 2025. Nothing here is opinion.
Share of tests where each item was recorded. The dark tick is the class average across all tracked models; bars are scaled within each group.
The rows that judge the model rather than its keeper. 10,908 tests in this band.
Tyres, pads and stone chips say more about how the car was driven and maintained than about how it was built.
Owner folklore from forums and the motoring press. Most of it never shows up in an MOT, which is why this section exists at all.
Cars fitted with the optional petrol range extender can develop fuel system problems from sitting unused for long stretches: sticking injectors, lambda sensor faults, corroded tank pressure sensors that lock the fuel flap, and fuel pump or relay failures that stop the generator kicking in when the battery gets low. BMW issued a recall in 2017 covering 2014-2017 REx cars after finding the fuel tank vent line could rub through on the battery positive cable and leak fuel vapour, a fire risk. Pump and sensor repairs typically run £300-£700 out of warranty. Doesn't apply to pure battery-electric i3s.
Owners report the high-voltage battery pack losing noticeable range over time, some seeing 20-30% down within a few years, though it's inconsistent: plenty of cars past 90,000 miles still hold close to their original figure. BMW's UK warranty (8 years/100,000 miles) covers packs that fall below a set capacity threshold, but an out-of-warranty pack replacement is one of the biggest bills the car can throw at you, running into thousands. Charging habits, especially frequent rapid charging, seem to be a factor.
The onboard charging control unit (BMW calls it the KLE) that manages AC and DC charging can fail, leaving the car charging slowly or not at all, and some owners have had a replacement unit fail again within months. Bills for a new unit have been reported at over £900 once out of warranty. There's no recall covering it, it's just one of the pricier used-i3 electrical gremlins.
The i3's CFRP passenger cell is light and strong but can't be repaired like a normal steel bodyshell, so even minor damage gets costly fast; one widely quoted example is around £800 just to replace a door mirror because of the dismantling involved. BMW trains specific dealers and bodyshops for CFRP repair, which is itself an acknowledgement of how specialised it is. It's not a fault so much as a trap: cars that look only lightly bumped can get written off, and poorly repaired ones can hide in the used market.
On higher-mileage cars the rear electric motor can develop a bearing whine, often around the resolver sensor, that's worse at low speed and eases off as you speed up, sometimes alongside clonks when selecting drive or reverse as the motor mount bushes wear. Because the fix means pulling the rear subframe and drivetrain apart, quotes have run from around £2,500 for a mount replacement up to £4,000-£6,500 for motor work, well above what you'd pay for engine mounts on a combustion rival.
The i3 runs unusually narrow, tall tyres in different sizes front and rear, and they wear unevenly: owners regularly report rears needing replacement at anywhere from 9,000 to 22,000 miles against 20,000-25,000 miles for the fronts, with alignment and the car's regenerative braking habits often blamed. The measured MOT data for this segment flags wheels as the standout fault area, and this lines up with what owners describe, though it reads more as tyres and tracking getting hammered on one axle than the wheels themselves failing.
Built from the two sections above.
Same segment (Family hatchbacks), best MOT record first. Compare before you shortlist.