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Common problems by part

Toyota iQ exhaust, emissions and leaks problems

DVSA MOT tests 2022–2025 · 15,128 MOT tests · Updated

At 13 years, 1.6 in 100 MOT tests of the Toyota iQ failed on exhaust, emissions and leaks, against 4.3 for all class 4 vehicles the same age (all test years; 15,128 MOT tests) [1].

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  • Against all class 4 vehicles the same age: fails less often than all class 4 vehicles the same age (0.3–0.4×) (all test years), 248 MOT tests with a fail
  • By age: seen at 8 ages from 9 to 16 years, 67,409 MOT tests
  • Most common fail: Malfunction indicator lamp: inoperative or indicates a malfunction, 0.6 per 100 MOT tests

Figures are for the model as a whole, not for one car.

What the MOT tests show

What we know

1.6 fails per 100 MOT tests at 13 years, against 4.3 for all class 4 vehicles tested at 13 (all test years). The Toyota iQ fails less often here.

Why it matters

An exhaust, emissions and leaks fail stops the car passing until it is fixed; the most common one is rated major by DVSA.

What to check

Start the car from cold and look for smoke at the exhaust, listen for blowing joints, and look under the engine and gearbox for fresh oil or fluid drips.

Toyota iQ exhaust, emissions and leaks fails by age

Toyota iQ exhaust, emissions and leaks fails per 100 MOT tests by ageSolid line: the Toyota iQ. Dashed line: all cars the same age. The table below lists every value.02469 years: 0.8 per 100 (all cars 2.4), 2,162 MOT tests910 years: 0.6 per 100 (all cars 2.8), 4,483 MOT tests1011 years: 1.0 per 100 (all cars 3.2), 7,051 MOT tests1112 years: 1.6 per 100 (all cars 3.7), 9,967 MOT tests1213 years: 1.6 per 100 (all cars 4.3), 15,128 MOT tests1314 years: 2.1 per 100 (all cars 5.1), 12,611 MOT tests1415 years: 2.2 per 100 (all cars 5.7), 9,943 MOT tests1516 years: 2.6 per 100 (all cars 6.2), 6,064 MOT tests16
Fails per 100 MOT tests by age, all first-use years pooled. Toyota iQ All class 4 vehicles the same age
AgeMOT testsFails per 100All class 4 vehicles the same age
92,1620.82.4
104,4830.62.8
117,0511.03.2
129,9671.63.7
1315,1281.64.3
1412,6112.15.1
159,9432.25.7
166,0642.66.2

All first-use years of the Toyota iQ pooled at each age, against all class 4 vehicles at that age over all 2022–2025 test years.

What fails in the exhaust, emissions and leaks at 13 years

Fails

Diagnose engine warning light cost

Repair figures are estimates, not quotes: how we estimate repair costs.

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How to check on a test drive

Start the car from cold and look for smoke at the exhaust, listen for blowing joints, and look under the engine and gearbox for fresh oil or fluid drips.

Check one Toyota iQ, not the average

The figures here describe Toyota iQ cars as a group. These free tools answer for one car. Each line says what the tool reads.

Other Toyota iQ problems

Exhaust, emissions and leaks on rival models

Questions people ask

Does the Toyota iQ have more exhaust, emissions and leaks problems than other cars?

0.3 to 0.4 times the exhaust, emissions and leaks fail rate of all class 4 vehicles the same age at 13 years (all test years), from 15,128 MOT tests. The interval is clear of 0.8 in the same direction at 5 of the 8 ages seen (ages up to 18 with at least 100 MOT tests with a fail).

How common are Toyota iQ exhaust, emissions and leaks problems?

1.6 in 100 MOT tests at 13 years failed on exhaust, emissions and leaks, against 4.3 for all class 4 vehicles the same age (all test years; 15,128 MOT tests).

What is the most common Toyota iQ exhaust, emissions and leaks fail?

0.6 in 100 MOT tests at 13 years: Malfunction indicator lamp: inoperative or indicates a malfunction (96 MOT tests with it).

Sources

  1. Driver and Vehicle Standards Agency, Anonymised MOT tests and results, 2022 to 2025. DVSA MOT data, Open Government Licence v3.0, 67,409 MOT tests. Accessed 7 Oct 2026.
  2. Office for National Statistics, Consumer price inflation, local price quotes (car repair items). ONS price quotes, series 610236. Accessed 7 Oct 2026.

Parts: against all class 4 vehicles at the same age, all 2022–2025 test years pooled, not adjusted for mileage. Breakdowns and non-MOT faults are not in this data. How we compare