Fiat
11,147 MOT tests analysed. sits above the UK fleet average — here's where 500 Lounge Mhevs pass, fail, and end up on the retest sheet.
That's 12.0 points above the UK fleet average across our 1,984 tracked models — a confident result.
Pass
89.5%
Pass-after-fix
2.8%
Fail
7.4%
Avg miles
20,369
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 · 11,147 tests
Pass rate climbs 1.0 points across the cohorts — newer 500 Lounge Mhev examples clear the test more reliably than the early cars.
Pass
89.0%
Fail
7.5%
PRS
3.1%
Avg mileage at test
20,652 mi
Pass
90.0%
Fail
7.3%
PRS
2.5%
Avg mileage at test
20,085 mi
Cohort = vehicle's first-registration year band. Same model, different generations of build.
The picture
Across 3,813 MOT tests, the 500 Lounge Mhev returns 88.8% first-time pass — comfortably ahead of the UK fleet average. The single most-logged Major fail is a tyre with the cords showing. A defective wiper blade and wipers that don't clear the screen round out the top three. Average tested mileage sits at 15,911, 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
A low-group car — among the cheapest to insure in the UK. 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 →
3–14
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A tyre cords visible or damaged
296 occurrences · 2.7% of tests
Tyre tread depth not in accordance with the requirements
143 occurrences · 1.3% of tests
Wiper blade defective
98 occurrences · 0.9% of tests
Wiper blade missing or obviously not clearing the windscreen
87 occurrences · 0.8% of tests
Windscreen or window damaged or seriously discoloured but not adversely affecting driver's view
80 occurrences · 0.7% of tests
A tyre seriously damaged
79 occurrences · 0.7% of tests
A tyre seriously damaged
34 occurrences · 0.3% of tests
A shock absorber damaged to the extent that it does not function or showing signs of severe leakage
30 occurrences · 0.3% of tests
A tyre pressure monitoring system malfunctioning or obviously inoperative
18 occurrences · 0.2% of tests
An obligatory rear fog lamp missing, or a front or rear fog lamp inoperative or in the case of a multiple light source more than 1/2 not functioning
15 occurrences · 0.1% 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 4 failures
£160–£280
If every one of this 500 Lounge 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 →
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Build your own retest budget.
Year-band analysis
First-time MOT pass rate split by registration band. A 1.0-point gap between bands is modest — the year you buy Fiat 500 Lounge Mhev makes a small but real difference to MOT outcomes.
Best band to buy
90.0%
2021+ registration
the 2021-on band climbs to 90.0% — a 1.0-point improvement. Failures here are mostly wear items: has ply or cords exposed, tread depth below requirements of 1.6mm — the structural issues that drag down older examples don't appear in the top-10 for this band. Post-2020 examples are early in their MOT life and generally show the cleanest records.
Band to be cautious about
89.0%
2018–2020 registration
On the 2018–2020 band, the data shows a 89.0% pass rate against a fleet average of 90.0% on the newer band. The main culprits logged at test: has ply or cords exposed, tread depth below requirements of 1.6mm, and does not clear the windscreen effectively. Average mileage on test for this band is 20,652 miles — high-mileage wear items are a recurring theme.
Best band to buy: 2021+ (90.0% first-time pass). Worst band to avoid: 2018-2020 (89.0% pass). That's a 1.0-point spread across 5,601 older tests and 5,546 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
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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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
Not very practical. Bouncy ride. Sluggish performance. In-car tech is behind the times.
Another case of hatchback lock failing because cables inside wiring loom had chafed in the hatchback hinge. All 500 owners should check for this.
Software fix available from some Fiat dealers that restores the performance of EU6 1.2 Panda and 500 engines.
Fiat 500 Dualogic would not select any gears and required new Actuator at a cost of £1800. Cost of repairs so far: £3,000.
Problem with EU6 compliant versions of 1.2 Fire engine in Fiat 500. Hesitation when pulling away in 1st and 2nd gears due to a ECU remapping to meet EU6. "Feels very unsafe, when trying to pull out into traffic."Apparently, some Fiat dealers have an ECU software fix for this. At a guess, it is probably to resture the ECU to the EU5 settings.
Another case of a 500 MultiJet diesel engine revving uncontrollably because the ECU had introduced too much fuel to the engine to actively regenerate the DPF, this fuel had sunk into the sump, and the sump level had risen sufficiently for the compression ignition engine to run on it. This car was a 25,000 mile 2008 500 MultiJet. Vital for all drivers of 500 MultiJet diesels to chack their sump levels regularly and if the oil seems to rise get their cars to a Fiat dealership for an oil change and forced regeneration of the DPF.
Second report of failed rear wiper and brake lights on a 4-year old 500 due to can bus wiring problems as a result of the cable loom getting trapped in the hatchback opening £400 to fix.
A 2010 Abarth 500 suffered the loss of various key functions including speedometer, indicators and brake lights (which of course makes the car illegal to drive). An independent garage traced the fault to the wiring cable under the tailgate. The wires had become twisted and broken as a result of the movement of the tailgate. Fault as origninally reported on 13-5-2012.
Heater matrix failure on 500 TwinAir led to overheating of engine.
Electric hatch lock failed twice on a 17,500 mile 2009/50 500: first time replaced under warranty; 2nd time dealer wanted £193.
Clutch mechanism of 2009/59 500 and electric hatchback lock failed at very low 2500 miles.
Yet another failed 1.3 Multijet reported. This was a 2008/58 that had done less than 14,000 miles. Active DPF regeneration had put too much diesel into the engine, effectively raising the sump level and causing the engine to run uncontrollably on its sump oil to the point of self-destruction. Vital for all drivers of 500 Multijet diesels to chack their sump levels regularly and if the oil seems to rise get their cars to a Fiat dealership for an oil change and forced regeneration of the DPF.
PAS failure on 20 month old 500C**.**
Source: honestjohn.co.uk · 29 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 500 Lounge 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.
