Avensis check engine light air valve

I had something similar happen with my Avensis, though it took me ages to figure it out. Is it perhaps the hose connection from the pump to the valve? That was my issue, the connection had become porous, a bit like an old rubber band, letting air escape. Caused all sorts of havoc with the air supply and engine management.

Interesting! When you say 'the hose connection from the pump to the valve', can you be a bit more specific? Where exactly should I be looking in the engine bay? Is it near the throttle body or closer to the air intake manifold? I'm guessing it's part of the secondary air injection system?

Yeah, that's the one. It's definitely part of the secondary air system. Honestly, unless you're super comfortable poking around, I'd just take it to a workshop. They'll be able to pressure test the system and pinpoint the leak pretty quickly. It's a pain, I know, but sometimes it's better than chasing your tail!

Thanks a bunch! I took your advice and brought it to a local shop. Turns out you were spot on, it was a defective hose connection from the pump to the valve! They replaced it, cleared the code, and now the check engine light is gone. Cost me 175€ all in. Appreciate the help!