Ok, so I got the 402 code, pulled the EGR valve and the thing was really dirty, based on other reviews, cleaning it may damage the diaphragm. So I replaced it. Brand new 142.00, code was cleared of course because I disco'd the neg terminal. a week later, P0402 re-appeared. I pulled the MAF sensor, sea foamed it, new air filter. Of course, it cleared again due to the neg terminal being removed, After a week it popped the code again.
So I did the following.
1) checked the check valve for proper operation, it passed OK
2) checked the EGR vacuum modulator, it passed OK
3) Engine off for about an hour, I checked OHMS as the EGR temp sensor.
with the meter set at 2000k, I read 100 OHMs, with the meter set at 20k, i get 0. I believe anything under 200OHM's shows a short. Can someone advise if I have tested this correctly?
I tried to pull the EGR temp sensor, and its really in there, I sprayed some PB blaster, let it soak, but still having issues, a 13mm doesnt fit, and a 14mm seems to have a little play. After some discussion I think i need to let it sit over night with some PB blaster soaking in, and then give it a try, but this is another 152.00 part, and I curious if this is the issue.
Speaking to a Toyota tech, he said, they always replace both the EGR valve and the temp sensor.
Wanted to see what you guys thought.
Thanks for any help