P0410 Secondary Air Injection System Malfunction

Not urgent

The ECU sees a problem in this circuit but cannot narrow it to a specific short or open. Start at the connector and the wiring before condemning the part.

Can you drive it? This is an emissions/EVAP fault. It will not hurt the engine and the car drives normally, but it will fail an emissions test and keeps the light on.

The definition

P0410: Secondary Air Injection System Malfunction.

P0410 is a powertrain code (the engine or gearbox), defined by the SAE standard - it means the same thing on any make of car, and any generic OBD-II reader will decode it.

What to check first

Cheapest and fastest checks first:

Read the freeze-frame data stored with the fault - engine speed, load and temperature at the moment it logged tell you whether this happens cold, hot or under load.
Check the connector at the part for corrosion, and that it is fully seated.
Clear the code and see whether it returns, and under what conditions.

What actually causes this on a VAG

Secondary air injection blows fresh air into the exhaust for the first minute or two after a cold start, so the catalytic converter heats up quickly and starts cleaning up sooner. On most VAG petrol engines that means an electric air pump, a one-way "combi" valve at the cylinder head that is opened by vacuum, and a small electric changeover solenoid (usually shown as N112 in diagnostic software) that switches that vacuum through to it. P0410 is the broad "this system isn't working" code. It's one of the most common faults on VAG petrol engines and it usually doesn't change how the car drives at all - though the warning light on its own will fail plenty of emissions and roadworthiness tests.

Most likely causes, in order

Seized combi valve at the cylinder head. Heat and carbon bake the one-way valve shut, so even a healthy pump can't push air into the exhaust. On a cold start you'll hear the pump run but nothing else changes. Testing whether the valve actually opens when vacuum is applied to it settles this quickly.
Split vacuum hoses or a dead changeover valve. The small hoses that carry vacuum to the combi valve perish, split at the ends or pop off, and the solenoid that switches that vacuum can fail with age. This is the cheapest part of the system to check - inspect and squeeze the hoses, and listen for the solenoid clicking when it's commanded on.
Pump relay, fuse or power feed. The pump draws a lot of current and has its own relay and fuse. Corroded relay contacts or a blown fuse give exactly the same silence as a dead pump. Check for power reaching the pump while the system is being commanded on, before condemning the pump itself.
Failed air pump. On a lot of VAG models the pump sits low at the front - behind the bumper or inside a wheel arch liner - where it gets wet and eventually dies. Either you hear nothing at all on a cold start, or you hear a grinding or rattling noise. The pump can be commanded on with a diagnostic output test to check it. It's the most expensive part of the system, so leave it until the cheap checks above are done.

Worth knowing: If the pump has failed, work out why before fitting a new one. The usual reason on these engines is that the combi valve has let hot exhaust gas and condensation back into the pump; fit a pump without sorting the valve and the new one commonly goes the same way. Also remember the system is only tested on a genuinely cold start, so you can't prove a repair by clearing the code and idling - it needs the car to stand and cool, ideally overnight, and then a cold start.

Reading the code is the easy part

A code names the circuit that complained. What tells you why is watching the sensor behind it while the engine runs — and that is where a code reader stops and a diagnostic tool starts.

VAGPULSE reads every module in a VW, Audi, Skoda or SEAT — not just the engine — shows the live measuring blocks behind this fault, gives you the freeze-frame conditions it was logged under, and clears it once you have fixed it. It also does what a generic OBD reader cannot on a VAG: service resets, coding, adaptations, and Stage 1–3 flashing with your original file saved first.

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Common questions

What does P0410 mean?

P0410 means Secondary Air Injection System Malfunction. The ECU sees a problem in this circuit but cannot narrow it to a specific short or open. Start at the connector and the wiring before condemning the part.

Can I drive with P0410?

This is an emissions/EVAP fault. It will not hurt the engine and the car drives normally, but it will fail an emissions test and keeps the light on.