If you are considering buying a used SEAT Mii, these are the common problems worth knowing about first. Our garage database tracks 2 known faults for this model. Every one below is a repair bill a seller has good reason not to mention.
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Is the SEAT Mii reliable?
The SEAT Mii has 2 known faults in our database, 0 of them rated high severity. The most serious are gearbox (the ASG automated manual gearbox the Mii shares with the VW Up) and safety (DVSA recall R/2013/058 (May 2013, 872 vehicles)). None of them makes the car a bad buy on its own; the risk is a seller who knows and says nothing.
That is a count of the faults we hold, not a reliability score. Popular cars get written about more, and a newer generation has had less time to show its faults.
Generation 1 of 12 known faults · 4 owner reports · 3 good notes
The ASG automated manual gearbox the Mii shares with the VW Up and Skoda Citigo gives trouble. In February 2014 a new Up with the same box sometimes would not select a gear when the lever was moved and stalled pulling away uphill from traffic lights, improving only partly after a software update. In March 2014 a Hi Up owner reported erratic changes taking one to two seconds and a car that sometimes would not move off without first selecting reverse.
Rough guide
£600-1500
Typical symptoms
gear lever moved but no gear selected
slow, jerky changes taking a second or two
stalling or rollback moving off on a hill
Affected vehicles
Engines:
1.0 with the ASG automated manual gearbox
🔍 We have a specific pre-purchase check for this faultCheck an advert →
Safety SystemsMedium severity🏛️ Official recall
DVSA recall R/2013/058 (May 2013, 872 vehicles): some Miis built from 14 January to 19 March 2013 had airbag control units programmed with the wrong parameters, which switched off the diagnostics for the side crash sensors, so a sensor fault would go unnoticed and the airbag warning light would not come on. VW and Skoda recalled the Up and Citigo for the same fault. The fix is free: the airbag control unit is reprogrammed.
Rough guide
£0 (free safety recall)
Typical symptoms
no airbag warning light even when a side crash sensor is faulty
often nothing a driver would notice
Affected vehicles
Engines:
All (cars in the recall build window)
🔍 We have a specific pre-purchase check for this faultCheck an advert →
What owners report on the Mk1
4 single reports, unconfirmed
One owner each, in their own words rewritten as a line, and not counted in our risk scoring. A fault joins the list above once a second report or an editorial source backs it.
Gearbox and clutch · October 2019A new SEAT Mii experienced difficulty engaging first gear, a complaint which the dealer dismissed.
Interior · September 2018The cabin ventilation, heater, and air conditioning fan motor failed in a SEAT Mii.
Gearbox and clutch · March 2014An automated manual gearbox on a Hi Up (similar to SEAT Mii) exhibited erratic gear changes and difficulty moving from stationary.
Gearbox and clutch · February 2014A new automated manual gearbox on an Up (similar to SEAT Mii) had issues selecting gears and stalled on hills.
What owners like about the Mk1
3 notes
This model offers good value for money and is very inexpensive to run.
Its compact dimensions make the car very easy to park in tight spaces.
The SEAT Mii offers generous interior space, providing ample room for front occupants and enhancing overall comfort.
Sellers rarely admit these faults outright
We track 5 specific phrases sellers use in adverts to soft-pedal these exact issues. Paste any SEAT Mii advert and we check it in seconds.
An overdue cambelt is the most expensive thing a seller can fail to mention on a used Mii. These are the figures UK specialists work to.
Timing belt (cambelt)Belt
MII 1.0 MPI, MII 1.0 60, MII 1.0 75
40,000 miles or 4 years, whichever comes first
The 1.0 three-cylinder shared with the VW Up and Skoda Citigo is belt driven, not chain, and the belt does not turn the water pump, which has its own belt. In 2016 dealers were quoting three years or 30,000 miles, which an owners' forum disputed, citing an official 100,000 miles; in 2018 owners of 2013 Miis were told the belt was due at five years, and a 2013 car reached 65,000 miles on its original belt by 2019. With the official figure disputed, change it at no more than four years or 40,000 miles; VW dealers offered the job on the Up for 150 pounds at the end of 2019.
Always confirm against the vehicle handbook. Intervals vary by engine, and several manufacturers revised theirs after failures in service.
Repair costs are typical UK ranges, not quotes. Actual cost depends on condition and garage.Data last verified: October 2026
SEAT Mii buying questions
What should I check when viewing a used SEAT Mii?
Ask the seller about the gearbox and safety faults on this page and whether they have been fixed, with invoices. On the test drive watch for gear lever moved but no gear selected and no airbag warning light even when a side crash sensor is faulty. Read the MOT history for repeat advisories, then paste the advert into the free check, which reads it against its known faults before you travel. Check a SEAT Mii advert →
What is the real MPG of a SEAT Mii?
Owners report 56.0 mpg on average across the SEAT Mii engines with data, about 81% of the official combined figure. The gap between official and real-world economy varies a lot by engine, so the Real MPG page lists every engine and generation separately, from 108 owner submissions. SEAT Mii Real MPG by engine →
If you used to check the Honest John “Good & Bad” section before the site closed in 2026, this page is where that information now lives. We rebuilt the SEAT Mii owner-report history from the archived Honest John dataset, added our own research, specialist and owner-club sources and DVSA recall data, and we keep it free. Each fault above is badged with its source. The same data feeds our free advert check, which reads a listing against every known fault for the exact engine and year.