2021 Kia Stonic Gt-Line S Isg Mhev S-A — MOT failures & pass rate

Across 1,042 MOT tests analysed for the 2021 Kia Stonic Gt-Line S Isg Mhev S-A, the most common recorded failure areas were visibility, brakes and lighting & signalling. Its pass rate of 96.4% was above the average for cars of a similar age (91.2%).

Pass rate

1,042

MOT tests analysed

3.6%

Fail rate

better than

vs cars of similar age

3.5

Avg age at test (yrs)

How it compares

Fail rate for this model-year against the segment and national averages for cars of a similar age.

Top failure categories

Most common MOT failure areas — 2021 Kia Stonic Gt-Line S Isg Mhev S-A
#	Category	% of tests affected	Tests
1	Visibility	2.7%	28
2	Brakes	1.3%	14
3	Lighting & signalling	0.9%	9
4	Tyres	0.9%	9
5	Steering	0.2%	2
6	Suspension	0.1%	1

Percentage of tests with at least one failure recorded in each category.

Most common specific failures

The exact components most often recorded as failures — more specific than the categories above.

Most frequently recorded failure items — 2021 Kia Stonic Gt-Line S Isg Mhev S-A
#	Failure item	Times recorded
1	Wipers	23
2	Brake pads	13
3	Headlamp aim	9
4	Washers	7
5	Tread depth	3
6	Track rod end	2

Top advisory categories

Advisories aren't failures, but they flag work likely needed soon — useful when budgeting.

Most common MOT advisories — 2021 Kia Stonic Gt-Line S Isg Mhev S-A
#	Category	% of tests with advisory	Tests
1	Tyres	10.4%	108
2	Brakes	5.8%	60
3	Other defects	4.4%	46
4	Visibility	1.8%	19
5	Steering	1.4%	15
6	Emissions & environmental	0.3%	3

Failure rate by mileage

Higher-mileage cars tend to fail more — often the most useful guide to real condition.

MOT fail rate by recorded mileage band.

Fail rate by recorded mileage — 2021 Stonic Gt-Line S Isg Mhev S-A
Mileage band	Tests	Fail rate
0-30k	837	2.9%
30-60k	194	5.7%

Failure rate by age

How this model-year's MOT fail rate climbs as the cars get older.

Trend over time

Fail rate by dataset year — 2021 Stonic Gt-Line S Isg Mhev S-A
Dataset year	Tests	Fail rate
2024	511	3.7%
2025	522	3.6%

What to check before buying a 2021 Stonic Gt-Line S Isg Mhev S-A

Before buying a 2021 Kia Stonic Gt-Line S Isg Mhev S-A, focus on the areas it most often fails on. Visibility accounted for 2.7% of tests for this year.

Visibility (2.7% of tests): Wipers, washers, mirrors and screen damage — usually inexpensive, but check for chips in the driver's line of sight. Typical repair: £15–£150.
Brakes (1.3% of tests): Pads/discs are routine wear; binding, imbalance or corroded pipes are more serious — test for pulling under braking. Typical repair: £100–£350 per axle.
Lighting & signalling (0.9% of tests): Often a cheap bulb, but persistent issues can mean wiring or corrosion in the units. Typical repair: £10–£150.

Repair costs are rough UK ballpark ranges to set expectations, not quotes — actual prices vary widely by car, parts and garage.

Frequently asked questions

How many 2021 Kia Stonic Gt-Line S Isg Mhev S-As pass their MOT?

96.4% of the 1,042 2021 Kia Stonic Gt-Line S Isg Mhev S-A MOT tests in this dataset passed — a 3.6% fail rate.

What is the most common MOT failure on a 2021 Kia Stonic Gt-Line S Isg Mhev S-A?

Visibility, recorded in 2.7% of tests, followed by brakes (1.3%).

Does the 2021 Stonic Gt-Line S Isg Mhev S-A get worse with mileage?

Its MOT fail rate rises from 2.9% in the 0-30k band to 5.7% in the 30-60k band.

Methodology & source. Based on 1,042 MOT tests. Dataset: DVSA MOT testing data (2021,2022,2023,2024,2025). Data last updated 2026-07-01. Figures reflect MOT-testable defects only — read the methodology for how these are calculated and what they don't measure.