Common problems

Peugeot 306 exhaust and emissions problems

How often MOT testers find exhaust, emissions and leaks faults on the Peugeot 306 at each age, against all cars of the same age, and which items come up most. From 14,057 DVSA MOT tests taken 2022 to 2025.

MOT data updated 28 September 2026

At 24 years, the most tested age

Exhaust, emissions and leaks fails per 100 MOTs (n=3,518)10.1

All cars at 24 years (n=428,815)7.0

Exhaust, emissions and leaks advisories and minor defects per 100 MOTs (n=3,518)21.0

All cars, same age (n=428,815)16.8

What stands out

At 24 years, 10.1 of every 100 MOTs of the Peugeot 306 found a exhaust, emissions and leaks fail (n=3,518), against 7.0 for all cars of that age (n=428,815).
It is above the all-car rate at 4 of the 5 ages with at least 1,000 tests.
The gap is widest at 23 years: 10.4 per 100 MOTs against 6.9 for all cars.
The exhaust, emissions and leaks fail item recorded most often at 24 years: catalyst emissions: Lambda reading after 2nd fast idle outside specified limits, on 3.3 per 100 MOTs.
The most common exhaust, emissions and leaks advisory or minor defect: engine oil leaks: leak, but not excessive, on 19.5 per 100 MOTs.

Exhaust, emissions and leaks fails by age

Solid line: this model. Dashed line: all cars at the same age.

Peugeot 306: exhaust, emissions and leaks fails and advisories per 100 MOTs, by age, against all cars. Ages with fewer than 1,000 tests are not shown.
Age	Tests (n)	Fails	All cars	Advisories	All cars
21 years	1,508	6.2	7.1	20.0	16.4
22 years	2,811	8.7	7.0	18.5	16.8
23 years	3,375	10.4	6.9	19.9	17.0
24 years	3,518	10.1	7.0	21.0	16.8
25 years	2,845	10.3	7.1	21.2	16.6

Exhaust, emissions and leaks fail items at 24 years

Exhaust, emissions and leaks fail items on the Peugeot 306 at 24 years (n=3,518), per 100 MOTs, with all cars at the same age (n=428,815).
Item	Per 100 MOTs	All cars
Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits	3.3	2.2
Catalyst emissions: carbon monoxide content after 2nd fast idle exceeds manufacturer's specified limits	2.9	1.4

Exhaust, emissions and leaks advisories and minor defects at 24 years

Advisories and minor defects are recorded, but the car still passes. Across all cars, a part with an advisory or minor defect failed at the next MOT 5.5 times in 100 (n=88,666,940 pairs of consecutive MOTs), against 0.3 times in 100 when the same part had none (n=12,936,860,350).

Exhaust, emissions and leaks advisories and minor defects on the Peugeot 306 at 24 years (n=3,518), per 100 MOTs, with all cars at the same age (n=428,815).
Item	Per 100 MOTs	All cars
Engine oil leaks: leak, but not excessive	19.5	15.1

What to check on a viewing

On the Peugeot 306, the exhaust, emissions and leaks items testers fail most are catalyst emissions: Lambda reading after 2nd fast idle outside specified limits; catalyst emissions: carbon monoxide content after 2nd fast idle exceeds manufacturer's specified limits.

Start the engine from cold if you can and watch the exhaust for blue or black smoke.
Check that the engine warning light goes out after starting and stays out on the test drive.
Look under the car and around the engine for oil or fluid leaks, and listen for a blowing exhaust.

Ask for the car's MOT history: a exhaust, emissions and leaks advisory that repeats from year to year has not been fixed. GOV.UK MOT history.

Questions

What are the common exhaust and emissions problems on the Peugeot 306?

At 24 years (3,518 MOTs), the exhaust, emissions and leaks fail items testers record most often are catalyst emissions: Lambda reading after 2nd fast idle outside specified limits (3.3 per 100 MOTs), catalyst emissions: carbon monoxide content after 2nd fast idle exceeds manufacturer's specified limits (2.9 per 100 MOTs). The most common exhaust, emissions and leaks advisories or minor defects are engine oil leaks: leak, but not excessive (19.5).

Does the Peugeot 306 have more exhaust and emissions problems than other cars?

At 24 years it has 10.1 exhaust, emissions and leaks fails per 100 MOTs against 7.0 for all cars of the same age (3.1 more). It is above the all-car rate at 4 of the 5 ages with enough tests.

Exhaust and emissions problems on other Peugeot models

Read this with care. A fail rate is not a measure of build quality. How far cars are driven, how they are used and how well owners maintain them all change it, and wear items such as tyres and brake pads are common fails. Compare a model only with cars of the same age. Methodology and limits.

The all cars figures cover all class 4 vehicles (cars and light vans) tested at the same age.

Looking at a Peugeot 306?

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Source

Contains public sector information licensed under the Open Government Licence v3.0. Source: DVSA anonymised MOT test data, class 4 normal MOT tests, 2022 to 2025. MOT data updated 28 September 2026.

Not affiliated with or endorsed by DVSA. How we calculate these figures · Data sources