Sc400 code 21 and 28
ok so after a long process of deleting my egr and fixing exhaust leaks, i finally have sealed the exhaust up. but now i have 2 codes, 21 and 28, which are for both main o2 sensors. I've had these codes before and it would alternate between them and lean afr when my exhaust was leaking.
Do you guys think my 02 sensors are actually bad? which would kinda make sense since its been running rich for a while (2-3 months)
or is there some other possible cause? it never had a code before i started messing with the egr system and exhaust .
It just doesn't make sense to me for them to both go out at the same time.
EDIT: its a soft code btw. it will be off when i go to start my car, and come back on after 10-15 minutes of driving.
and i am currently catless, straight pipe to the oem secondary mufflers. i had gotten 90 degree o2 defoulers but they wont fit on the sub 02 sensor bungs because they are angled. im not sure if this would be a cause as well, but if it was id think it would jsut throw a lean code right?
I did search a lot for people having both codes and didnt find anything, if there is a thread explaning this problem, I apologize. please direct me to it.
Last edited by Tam4511; 04-27-13 at 07:22 AM.