Catalyst emissions: Lambda reading after 2nd fast idle outside specified limits
This one item accounted for 0% of every MOT test carried out in Great Britain, and it is among the commonest faults on 24 different model-and-year combinations. Here is where it clusters, and what it looks like on a car you are standing in front of.
How to spot it before you buy
Check the dash for a DPF or emissions warning and ask when it was last regenerated
A blocked DPF on a car used for short trips is a common, expensive fault (£300–1,500+).
The models it hits hardest
Ranked by how often the fault came up as a share of that model's own tests, not by raw count — a fault in 8% of a small model's tests says more about that model than one in 3% of the Fiesta's. A linked row has a page of its own.
| Model | Years | Share of its tests |
|---|---|---|
| Volkswagen Fox | 2010–2013 | 4.7% |
| Peugeot 208 | 2010–2013 | 3.8% |
| Fiat Punto Evo | 2010–2013 | 3.7% |
| Mazda 5 | 2010–2013 | 3.3% |
| Fiat 500 C | 2010–2013 | 3.2% |
| Fiat Punto | 2010–2013 | 3.1% |
| Renault Twingo | 2014–2017 | 2.8% |
| Smart (Mcc) Forfour | 2014–2017 | 2.2% |
| Alfa Romeo Mito | 2010–2013 | 2.1% |
| Alfa Romeo Mito | 2014–2017 | 1.9% |
| Abarth 500 | 2010–2013 | 1.8% |
| Citroen C1 | 2010–2013 | 1.7% |
| Peugeot 208 | 2014–2017 | 1.6% |
| Peugeot 107 | 2010–2013 | 1.6% |
| Ford Ecosport | 2014–2017 | 1.5% |
| Smart (Mcc) Fortwo | 2014–2017 | 1.3% |
| Fiat 500X | 2018–2021 | 1.1% |
| Toyota GT86 | 2010–2013 | 1.1% |
| Skoda Citigo | 2014–2017 | 1% |
| SEAT Mii | 2014–2017 | 1% |
Showing the worst 20 of 24 affected model-and-year combinations. The full dataset is downloadable below.
Which manufacturers it clusters on
Pooled across each make's whole range, so this is a fact about the brand rather than about one of its models. Makes with at least 50,000 tests.
- 2.1% Peugeot
- 1.7% Citroen
- 1.4% Volkswagen
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See whether the car you're looking at has this on record
Type the registration and you get that car's own MOT history — every advisory and every failure, including whether this one has already come up.
Source: DVSA anonymised MOT tests and results, 2023. Class 4 standard tests only. Contains public sector information licensed under the Open Government Licence v3.0.