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Known fault

Secondary air system: pump and combination valve (P0411)

It does not show up on every car. Check before you buy.

comfort

severity

not available

mileage

2

sources

2 sources next to the write-up.

The fault

How you spot it

From the late nineties to around 2006, petrol engines used a secondary air pump to blow fresh air into the exhaust on a cold start, so the catalytic converter reaches operating temperature faster. The impeller of the pump rusts or its bearing seizes, soot clogs the combination valve (N112), and the rubber hoses crack. The control unit then stores the `P0411` code. It barely affects driving, but the engine warning light is on, and the emissions test can fail because of it, and the roadworthiness test with it.

Which model

Who it affects

The card opens the generation, the engine or the transmission.

Engines and transmissions

Checklist

Secondary air system: pump and combination valve (P0411)

What you would check for this fault. Take it to the car.

Before you buy

Checklist

What you tick stays on this device only.

vinkodex.com · Before you buy it, see what can go wrong.

Sources

How we know

Information, not an expert opinion

We write the descriptions, and we put the source next to them. A person reviews them before they go out. They are still information, not a technical expert opinion.

  • A fault on the list does not mean the car you are looking at has it.
  • A fault missing from the list does not mean the model is fault-free. Write-ups are made model by model. Not all of them are done.
  • You decide whether to buy. This is no substitute for an inspection. That needs a workshop and a history check.
Details in the terms