P0410
Secondary Air Injection System
- Severity
- Low
- Driving
- Drivable — book it in
A general fault in the secondary air injection system. This system pumps fresh air into the exhaust for a minute or two after a cold start. The extra oxygen lets unburnt fuel finish burning in the exhaust, which cuts emissions during the dirtiest part of a journey and warms the catalytic converter up faster. It only runs briefly and only when cold, which is why a fault here usually changes nothing the driver can feel.
Possible causes
- CommonFailed air pump - very often seized after ingesting water
- CommonFailed one-way check valve letting exhaust gas back into the pump
- CommonBlocked or corroded air passages into the exhaust manifold
- CommonFailed switching or control valve
- PossibleSplit, perished or disconnected hoses
- PossibleBlown fuse or failed relay on the pump circuit
What you might notice
- Check engine light on
- Failed emissions test
- Loud noise from the engine bay for a minute or so after a cold start, or the absence of a noise that used to happen
- Rough running for the first minute from cold
- Frequently no symptom at all
What to check, in order
- Test from a genuinely cold start. The system only runs for a minute or two after starting a cold engine, so a warm restart will not reproduce the fault however far you drive.
- Listen on a cold start. A working pump makes an obvious whirring or buzzing noise for a minute; silence when there used to be noise is a clear finding.
- Check the fuse and relay for the pump before anything mechanical.
- Inspect the hoses between the pump, the valve and the exhaust for splits and disconnection.
- Check the one-way check valve. If it has failed, exhaust gas and moisture have been reaching the pump, and the pump is probably the next thing to fail.
- Check the air passages into the exhaust manifold for carbon blockage on a high-mileage engine.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Auxiliary emission controls
P0400P0401P0402P0403P0404P0405P0406P0407P0408P0409P0410P0411P0412P0413P0414P0415P0416P0417P0418P0419P0420P0421P0422P0423P0424P0425P0426P0427P0428P0429P0430P0431P0432P0433P0434P0435P0436P0437P0438P0439P0440P0441P0442P0443P0444P0445P0446P0447P0448P0449P0450P0451P0452P0453P0454P0455P0456P0457P0458P0459P0460P0461P0462P0463P0464P0465P0466P0467P0468P0469P0470P0471P0472P0473P0474P0475P0476P0477P0478P0479P0480P0481P0482P0483P0484P0485P0486P0487P0488P0489P0490P0491P0492P0493P0494P0495P0496P0497P0498P0499