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P0411: Secondary air injection incorrect flow detected

The ECU sees that secondary air is not reaching the exhaust properly after a cold start. Usually a stuck valve, a split hose or the pump.

Code P0411 at a glance
CodeP0411
SystemEngine and transmission
GroupP04xx, Emissions control
TypeGeneric: it means the same on every make
Can you keep driving?Yes, no rush

What P0411 means

After a cold start, the secondary air pump pushes air into the exhaust and the oxygen sensor should detect a lean mixture. If the sensor does not see it, or sees it when it should not, the ECU stores this code.

Most common causes

  • Check valve stuck with carbon
  • Loose or split secondary air hose
  • Weak air pump or water inside it
  • Switching valve that does not open or close
  • Blocked air passages in the cylinder head
  • Slow oxygen sensor that fails to detect the air

Symptoms

  • Engine warning light on
  • Pump sounds different from normal
  • Failing an emissions test
  • Usually no change in how the car drives

Can you drive with P0411?

Yes, no rush It only affects the first few minutes from cold, so you can drive normally. Worth fixing before the next inspection.

How to check it

On a cold start, watch the upstream oxygen sensor voltage on your reader: with secondary air working it should stay low (lean) for the first minute.

How to read and clear P0411 with Final OBD

Plug an OBD2 scanner in under the steering wheel, switch the ignition on and open Final OBD. Under Faults you’ll see P0411 with this same explanation and whether it’s confirmed, pending or permanent.

With Free you read this code with its short description for nothing, and clear it if the engine stores it over standard OBD. With Pro you get the full explanation, how the car was running when it was logged (revs, temperature, load) and clearing in every control unit.

Clearing the code only turns the light off: if the cause is still there, it comes back. Clear it once it’s fixed, and not right before the ITV. It’s all in how to read and clear fault codes and in the ITV and OBD.

Similar codes

P0411 is a generic code, so it means the same on any make, for example on Abarth, Cupra, Jeep, Nissan, Seat, Škoda. See what Final OBD does on your car in makes and models.

What does code P0411 mean?

After a cold start, the secondary air pump pushes air into the exhaust and the oxygen sensor should detect a lean mixture. If the sensor does not see it, or sees it when it should not, the ECU stores this code.

Can you drive with P0411?

It only affects the first few minutes from cold, so you can drive normally. Worth fixing before the next inspection.

How do you clear P0411?

With an OBD2 scanner and an app like Final OBD, which clears it for free if it’s stored by the engine control unit. But clearing it only turns the light off: if the cause isn’t fixed, P0411 comes back.