P2004 code shows up when brakes are pumped.

[ExpandWeiner]

So I've found out that if I pump my brakes while standing still for about 20 seconds, the check engine light will always come on. The code is P2004 and is something about an intake manifold runner flap being stuck open. Seems really odd to me. Nothing about the behaviour of the engine changes before/after the light comes on. Anyone had this happen?

 

[Channel Hopper]

The only link I can see is a loss in vacuum as the brake master cylinder operates. With luck it will be a loose clamp or possibly a perishing pipe, which you can trace with some spray grease.

 

[F6HAD]

Never seen this happen but I also thought the same thing, sounds like a vacuum leak. Check the IMRC isn’t split or broken and follow the vacuum lines to check for a break somewhere.