Cause
Water damage to the air pump
Water reaching the secondary air injection pump and destroying it. The pump is an electric motor that only runs for a minute after a cold start, and it sits low in the engine bay drawing air from a wheel arch — so water arrives from spray, from washing, or backwards through a failed check valve.
Exhaust condensation is the route people miss. The exhaust side of this system is full of water vapour, and a check valve that no longer seals lets it condense inside the pump housing. So a water-damaged pump argues for inspecting the check valve in the same visit — a new pump behind a failed valve has a known expiry date, which is why these fail in pairs.
Typically a moderate job.
Codes this can cause (1)
Codes where this is a likely explanation first, rather than merely a possible one.
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Others who found this
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about Water damage to the air pump.