Need a little help on the process to pass emissions with MHD on my N54

[Dekdo]

So i just bought a 135 and will be taking it to Illinois to get registered. It’s currently on MHD stage 2 with VRSF Catless downpipes and a muffler delete (if that matters). I’ve read that it can pass with MHD, but do I need to set it back to stock stage 0 or can I leave it at stage 2?

Also I see that VRSF sells a n55 dp fix but not an n54 dp fix... will the n55 dp fix work?

I’ve also read that you can pass with MHD without using a dp fix.. if so how?

Thanks for the help!

[JM98]

It depends on the state. For instance, in Texas you are allowed to have one of the readiness monitors unavailable, which is what MHD does to disable the catalytic converter check engine light, so there is no need to tune back to stock or do a DP fix.

If your state allows 0 monitors to be unavailable, then you will need to flash to stock and do the physical DP fix.

[Dekdo]

Originally Posted by JM98

It depends on the state. For instance, in Texas you are allowed to have one of the readiness monitors unavailable, which is what MHD does to disable the catalytic converter check engine light, so there is no need to tune back to stock or do a DP fix.

If your state allows 0 monitors to be unavailable, then you will need to flash to stock and do the physical DP fix.

I’m in Illinois and looks like we are allowed 1 to be unavailable.

Edit: From https://illinoisairteam.net/vehicle-...-testing-faqs/
"when more than one (1) non-continuous readiness monitor is “not ready” for 2001 and newer model year vehicles. Additionally, the catalyst monitor must be “ready” at the time of any retest after a vehicle failed an initial test for any catalyst code."

Looks like i should be ok then. If i were to fail for some reason then it sounds like id need to do a drive cycle? or would i have to go back to stock and then do a drive cycle?

[JM98]

Originally Posted by Dekdo

I’m in Illinois and looks like we are allowed 1 to be unavailable.

Edit: From https://illinoisairteam.net/vehicle-...-testing-faqs/
"when more than one (1) non-continuous readiness monitor is “not ready” for 2001 and newer model year vehicles. Additionally, the catalyst monitor must be “ready” at the time of any retest after a vehicle failed an initial test for any catalyst code."

Looks like i should be ok then. If i were to fail for some reason then it sounds like id need to do a drive cycle? or would i have to go back to stock and then do a drive cycle?

Depends on the fail reason. You only need to drive cycle if you recently reflashed. You can check readiness monitors with MHD though