I'm trying to clean out my cat enough to hopefully pass emissions test. I want to Seafoam the engine, but am uncertain exactly which hose to put the fluid into.
I've watched a lot of videos but would really appreciate a picture or diagram if someone could set me straight.

My van flipped a 2040 code.

Thanks!

 

so people are saying this fixes a p0420 low cat efficiency dtc are they? post how it works out. go easy and don't hydrolock the motor.
follow the brake booster hose back to the throttle body.