P0492
Secondary Air Injection System Insufficient Flow (Bank 2)
- Severity
- Low
- Driving
- Drivable — book it in
Not enough secondary air is reaching the exhaust on bank 2. Because the module names one bank rather than the whole system, this points at something specific to that side - a blocked passage, a stuck valve or a failed check valve on bank 2 - rather than at the pump, which usually feeds both.
Possible causes
- CommonCarbon blocking the air passage into the bank 2 exhaust manifold
- CommonCheck valve on bank 2 failed or blocked
- CommonSwitching valve for bank 2 stuck closed
- PossibleSplit or disconnected hose on bank 2
- PossibleWeak air pump - though this usually affects both banks
- PossibleFaulty flow sensor on bank 2
What you might notice
- Check engine light on
- Failed emissions test
- Rough running for the first minute from cold
- Often no symptom the driver notices
What to check, in order
- Test from a genuinely cold start.
- Note that only one bank has faulted. That rules out the pump as a sole cause and directs everything at the bank 2 plumbing.
- Check the hose and check valve on bank 2 first.
- Inspect the air passage into the bank 2 exhaust manifold for carbon.
- Compare the two banks. Whatever is different between them is the fault.
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