VW Up quality at a SEAT price tag
SEAT's version of the VW Up trio, the Mii was sold from 2012 to 2019 and offers the same proven mechanicals as the Up and Skoda Citigo but typically at the lowest price of the three. A dependable city car with solid build quality that far exceeds what its size might suggest.
We track 5 known issues across the Seat MII range, with 3 classified as significant. Knowing which variants and configurations to approach with caution can save you from expensive surprises after purchase.
Found a Seat MII? Enter the reg to see which of our 5 known issues apply to that exact car, plus full MOT history and mileage checks.
MK1 (2012–2020) — Engine options included the 1.0 MPI. We track 5 known issues on this generation, with 3 classified as significant. The most significant concern is Fuel system leakage including filler cap issues (£25–£80 to address).
The Mii exhibits fuel system leakage at rates significantly above the fleet average, particularly affecting the fuel filler cap seal and associated components. MOT data shows this model fails at 30.2 times the national average for fuel system leakage, with the highest failure rate occurring between 20,000-40,000 miles. The issue encompasses both actual fuel leakage and ineffective filler cap sealing, which can cause fuel vapour emissions and potential fire risk.
Fuel leakage creates a fire risk and will result in MOT failure. Minor leaks may only be apparent during filling or when the tank is full. Fuel vapour emissions can also trigger the check engine light and cause emissions test failures.
Check for fuel smells around the engine bay and underneath the car. Look for staining or wetness around fuel lines and connections. Injector issues may cause rough running or misfires that are most noticeable at idle.
The Mii shows significantly higher emissions failure rates than the fleet average, with failures occurring at 13.9 times the national rate for exceeding default limits and 9.2 times for exceeding manufacturer limits. Peak failures occur between 20,000-40,000 miles, suggesting issues with emissions control components during the early to mid-life period. This affects both lambda sensor readings and overall exhaust gas composition.
Emissions failures result in immediate MOT failure and the car cannot be legally driven on public roads until repaired. Root causes can include faulty lambda sensors, catalytic converter degradation, or engine management system issues requiring diagnostic equipment to identify.
Check for any engine warning lights on the dashboard. Ask about the car's MOT emissions history — repeated failures suggest underlying issues. A pre-purchase diagnostic scan is especially worthwhile to check for stored emissions fault codes.
The Mii experiences brake binding at rates significantly above average, with MOT data showing failures at 4.2 times the fleet rate for significant brake effort with no brake applied. This indicates seized or sticking brake calipers, corroded brake slides, or problems with the brake hydraulic system causing brakes to remain partially applied when they should be released.
Binding brakes cause rapid pad and disc wear, reduced fuel economy, and can lead to brake fade or failure under heavy use. The affected brake can overheat and lose effectiveness when needed for emergency stopping. Continued driving with binding brakes will require expensive disc and pad replacement.
Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.
The handbrake mechanism on the Mii requires adjustment more frequently than typical, with MOT failures occurring at 8.0 times the fleet average for excessive lever travel. The issue peaks at high mileage but can occur from 20,000 miles onwards, suggesting the adjustment mechanism or cable system has inherent wear characteristics that require more frequent attention than competitors.
Excessive handbrake travel will cause MOT failure and reduces the effectiveness of the parking brake. While not immediately dangerous, a poorly adjusted handbrake may not hold the car securely on slopes and is a legal requirement for roadworthiness.
Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.
MOT data shows the Mii experiences excessive brake disc fluctuation at 3.1 times the fleet average, indicating warped or unevenly worn brake discs. This issue peaks at high mileage but can develop from around 40,000 miles. The problem likely stems from the interaction between the brake binding issues and the disc material or design characteristics specific to this model.
Warped brake discs reduce braking efficiency and cause uncomfortable pulsing during braking. Severely warped discs can cause longer stopping distances and uneven brake pad wear. The discs will need machining or replacement depending on thickness and severity of warping.
Check brake disc condition for lipping or scoring. Test braking at moderate speed for pulling to one side or vibration through the steering wheel. Review MOT advisories for brake-related items.
For the full breakdown of all 5 tracked issues with repair costs, see the Seat MII common problems page.
Based on 90k real DVSA MOT tests, the Seat MII fails more often than average on several items. The biggest outlier is lamp missing, inoperative or in the case of a m... at 89x the fleet average, followed by fire risk due to fuel tank shield or exhaust sh... (64x).
When viewing a specific car, check its MOT history for recurring advisories in these categories. See the full Seat MII MOT failure breakdown for data at every mileage point.
Routine servicing (oil and filter change every 10k miles) typically costs £80–£120 at an independent garage.
See the full Seat MII service schedule for every interval and cost breakdown.
The Seat MII is a solid choice on the used market, though not without its quirks. The issues we track are well-understood and largely avoidable if you know what to look for. A thorough inspection and complete service history go a long way. 2015-2017 models offer the best reliability (defect rates dropped steadily from launch) and benefit from early-year improvements. The 74hp 1.0 is worth seeking out over the 59hp for motorway ability. Five-door versions add only modest cost but much more practicality.
Before committing, check the car's full MOT history, verify the service record is complete, and if possible arrange a specialist inspection. Enter any registration into our free report to see the complete picture.
Get Car Wise maintains a database of known mechanical issues for every popular car on UK roads, tracking the faults that owners, specialists and DVSA data reveal.
When you run a report on a specific Seat MII, we cross-reference the exact variant, engine and age against our database of 5 known issues. Combined with full MOT history analysis, mileage verification and DVLA data, you get a complete picture before viewing.
Enter the registration for MOT history, mileage verification, known faults for that exact variant, and a Get Car Wise Score.
This guide was compiled from independent expert reviews, DVSA MOT data, specialist workshops and our own database of 5 known Seat MII issues. We are not affiliated with any source listed.