I have a 96 sc300 5 speed with about 120k miles.
I have the p0401 insufficient egr flow code.

Recently I did a full tune up cleaned out intake manifold
my throttle body and low to no carbon build up

Egr valve had tons of carbon in it cleaned it out with carb cleaner
vacuum tested egr looks like its working fine
gave it vacuum when car was on no change in idle

As of now i have no idle or any issue car runs great

any help is appreciated im trying to pass CA smog but that cel wont let me :[

 

take a 1k ohm resistor and stick it into the plug of the sensor responsible for this. might work. I've used that value for egr stuff on an obd2 supra before. can't remember if it was that exact code but the number seems familiar. If it works you might wanna clip the wirea about 3" off the clip, connect the wires with the resistor from where you clipped, use heat shrink or tape over your connection, then tape around that and the clip with pigtail and plug it in to make it look like all is functioning as it should for a visual. good luck.

 

Iv heard of the resistor trick but doing that wont pass my numbers for me
Im trying to get advice on how to fix this issue

i read it could be the vsv, vacuum modulator, or even carbon inside manifold just dont know how to go about it
took it to a shop they just guessed around and threw prices at me...