Ford
14,245 MOT tests analysed. sits above the UK fleet average — here's where Fiesta ST Line Edition T Mhevs pass, fail, and end up on the retest sheet.
That's 11.5 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
89.0%
Pass-after-fix
4.7%
Fail
6.0%
Avg miles
25,040
Pass + Pass-after-fix + Fail = 100%
Petrol cars first registered from January 2006 meet Euro 4 — compliant in London ULEZ, Birmingham CAZ, Bristol CAZ, and Glasgow LEZ.
Performance by cohort
2 year bands · 14,245 tests
Pass rate is broadly flat across the cohorts — new and old Fiesta ST Line Edition T Mhev examples track each other at the test bay.
Pass
89.5%
Fail
6.8%
PRS
3.5%
Avg mileage at test
28,239 mi
Pass
88.6%
Fail
5.5%
PRS
5.6%
Avg mileage at test
22,731 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.
The picture
Across 3,945 MOT tests, the Fiesta St-Line Edition T Mhev returns 87.9% first-time pass — comfortably ahead of the UK fleet average. The single most-logged Major fail is tyre tread under the limit. A seriously damaged tyre and headlamp aim out of spec round out the top three. Average tested mileage sits at 21,008, which is the lens to read those failure rankings through. If you own one and the next test is close, the ranked list below is a sensible pre-test checklist.
ABI Insurance Group
Below the fleet average — generally reasonable to insure. Lower groups cost less to insure; UK fleet average is around Group 22.
Source: ABI Group Rating Panel · administered by Thatcham Research · groups cover standard variants; performance trims may sit higher. Browse all insurance groups →
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Tyre tread depth not in accordance with the requirements
252 occurrences · 1.8% of tests
A tyre seriously damaged
105 occurrences · 0.7% of tests
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
96 occurrences · 0.7% of tests
The aim of a headlamp is not within limits laid down in the requirements
79 occurrences · 0.6% of tests
Wiper blade defective
56 occurrences · 0.4% of tests
Windscreen washers not working or not providing sufficient fluid to clear the windscreen
49 occurrences · 0.3% of tests
A tyre seriously damaged
49 occurrences · 0.3% of tests
a brake lining or pad worn below 1.5mm
38 occurrences · 0.3% of tests
Wiper blade missing or obviously not clearing the windscreen
32 occurrences · 0.2% of tests
A tyre cords visible or damaged
31 occurrences · 0.2% of tests
Counts cover Major and Dangerous defects logged at test. Advisory items excluded so this shows why a car was rejected, not just what the tester flagged in passing.
Worst-case fix budget · top 3 failures
£90–£220
If every one of this Fiesta ST Line Edition T Mhev's most-logged Major fails hit at the same MOT, that's the real-world UK garage range. Reality is usually one or two items, not all of them. Open the estimator →
Try the calculator
Build your own retest budget.
Year-band analysis
First-time MOT pass rate split by registration band. Pass rates barely move across bands here, so the year you buy Ford Fiesta ST Line Edition T Mhev makes little measurable difference to MOT outcomes.
Best band to buy
89.5%
2018–2020 registration
the 2018–2020 band climbs to 89.5% — a 0.9-point improvement. Failures here are mostly wear items: tread depth below requirements of 1.6mm, has a cut in excess of the… — the structural issues that drag down older examples don't appear in the top-10 for this band.
Band to be cautious about
88.6%
2021+ registration
On the 2021-on band, the data shows a 88.6% pass rate against a fleet average of 89.5% on the newer band. The main culprits logged at test: tread depth below requirements of 1.6mm, damaged but not adversely affecting driver's view, and too low. Average mileage on test for this band is 22,731 miles — high-mileage wear items are a recurring theme.
Best band to buy: 2018-2020 (89.5% first-time pass). Worst band to avoid: 2021+ (88.6% pass). That's a 0.9-point spread across 8,277 older tests and 5,968 newer ones — year of build makes a material difference on this model.
Picked against this car's top failure patterns. Affiliate links to Amazon UK — we earn a small cut at no cost to you. Disclosed up-front, doesn't shape the data.
Item 01 · Amazon UK
Digital tyre-tread depth gauge
Five quid for a gauge beats £150 for a retest. UK MOT minimum is 1.6mm — most testers fail anything below 2mm to be safe.
Search Amazon UK
Item 02 · Amazon UK
Headlight restoration kit
Yellowed lenses fail the light-output test. A restoration kit lifts the haze in an afternoon for £20.
Search Amazon UK
Item 03 · Amazon UK
Bosch Aerotwin wiper blades
Cheap wipers fail the test on smear streaks. Bosch Aerotwins last a winter and clear a screen properly.
Search Amazon UK
My Motor World · affiliate
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Mobile mechanic · UK-wide
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Owner reports · Honest John
Verbatim faults logged by owners on honestjohn.co.uk over recent years. We didn't summarise — these are the words people typed in.
What's good
The Ford Fiesta is the first car many people ever drive and, for many, it’s all the car they will ever need. Its versatility, low running costs and practicality are all at their best in this generation of Ford’s superlative hatchback.
Where it falls short
Several Fiesta models including Vignale now list at more than £20,000.
Report of a one year old Ford Fiesta Ecoboost MHEV where the 12v battery keeps running down so the air con will not work.
Heater failure on 2017 Ford Fiesta 1.0 EcoBoost The heater fan ceased to work on two occasions in any position except four, the highest. Each time the repair was done by fitting a new resistor. The latest repair failed again. Ford dealer now thinks that to effect a proper repair a new heater motor will have to be fitted. They say that five and a half hours labour will be required as access has to be carried out through the dashboard. The new motor will cost approximately £400 and the total bill will come to just over £1000. Unclear if the dealer or Ford will contribute towards the cost of the repair.
Problems reported with 2021 1.0 mHEV Fiesta. After three weeks of ownership there were problems with the passenger door touch sensitive unlocking. Owner took the car back to the dealer who said it was because the 12v battery was low (40 per cent). They suggested that because the owner only does around 100 miles a week and the hybrid system is only really charging the hybrid battery, so the standard one is likely to regularly run down.
Report of 2020 Ford Fiesta breaking down on the drive home from the dealership. Engine warning light appeared on the dashboard with the message "low oil pressure". Dealership recovered the car and stated it needed parts to be ordered from Germany and the owner would have the car back in a week. Owner is rejecting the car under the consumer rights act 2015.
Complaint about Sync3 not working in a 2018 Ford Fiesta 1.0 Ecoboost ST-Line automatic. The Sync 3 system includes the Sat Nav, yet, even though it has WiFi it doesn’t update. Owner has tried downloading satnav updates to a USB to update but it doesn’t work. Sat nav goes blank, all roads disappear and he can only see the red arrow. This happens just about every day. The car has been back to the dealers and they have applied all available updates but confirm it’s not fixed until Ford provides a permanent fix. Owner having to try to use Apple Carplay and Google Maps.
Report of audible warning and light coming on in brand new Ford Fiesta 1.0 Ecoboost, then going off before driver can work out what it is for. It will be the petrol particulate filter warning which then self-cleans so the warning goes off.
Report of battery regularly going flat in a 2017 Ford Fiesta.
Strange issue reported with June 2018 Ford Fiesta 1.1 Titanium, bought used at 5199 miles in May 2019. Yellow spanner came up on the display (indicating a malfunction) and the engine lost power for about 5-6seconds, then regained full power, carried on for about a quarter of a mile and lost power again.
Report of stop-start function of new shape 2017 Fiesta 1.0litre Auto only cutting in on a couple of ocassions since purchase used 12 months previously. Back to the dealer twice but each time they say cannot find anything wrong with diagnostics. Owner says battery cannot be being charged sufficiently or is faulty otherwise the function would work. Does reasonable mileages and have had the battery go flat when car was unused for 4 days.
Complaint of 2017/67 Ford Fiesta refusing to unlock with the fob or the spare. Called AA who told her how to open the car manually with the hidden key, but that it's a known Fiesta fault where the keys forget the car and require a "software update". Both keys started working again. Supplying dealer said all they could do was replace both batteries and refused to acknowledge the fact that both keys miraculously started working again. Ford UK has denied any knowledge of an issue or a software update.
Report of 2017 new model Fiesta bought new in November 2017 running down its battery after having been left unused for 2-3 weeks.
Report of failure of the manual transmission of a 2018 Ford Fiesta 1.1 Zetec bought at 9 months old. On attempting to drive it home the new owner found he could not change gear. The car was then recovered by the AA, returned to the showroom and owner demanded a return of the vehicle and an immediate refund, which he eventually got in full. The Ford dealer subsequently informed him that this was, apparently, an occasional problem on Fiestas.
Source: honestjohn.co.uk · 13 reports indexed, top 12 shown
Use the failure ranking as a pre-test checklist or a haggling lever. Treat the headline pass rate as a fleet-wide trend, not a guarantee on any individual car.
If you own a Fiesta ST Line Edition T Mhev and your last MOT looked nothing like the ranked failures above, that's normal — individual cars vary widely. The ranking shows the patterns testers flag most often across the country.
