Wont let egr, evap, or cat monitors set. Any suggestions? Reset egr and cat when I unplugged it but throws a p0171 lean code. I am n/a right now so no extra air is coming in. 2003 ls. Has a boomslang harness.

 

Here are the readiness requirements for each monitor to run (generally speaking).

Remember you can have one (or two depending on your state) that haven't run but all the rest MUST have run and you must not be displaying a check engine light.



You can look in the FSM for the OBDII drive cycle. It's a pain in the *** and very involved. It will take a day or two to fully run all the tests IF You do it by the book.

 

kinda helpful. Like i said i got it to pass (one not ready in tx). But why is the emu not letting them set, but also not throwing a CEL? EMU shouldnt do anyhting with EGR, or EVAP, but I know CAT moniter has to set before those will.

I did the drive cycle a bunch of times and it never set. but as soon as it was unhooked, it set two (but threw cel for lean if i went over 3k rpms)

will a bad rear o2 sensor do this? it has a spliced in replacement one from sometime before I got it. (weak heater circuit that hasnt failed completely??

 

if the monitors aren't ready, they wont ever throw a code...

you're doing ALL of the drive cycles from the 2003 FSM?

If any of the sensors required are out of range, the ECU wont run the monitor.

Does the EMU connect to the MAF?

Having O2 sensors way out of range could be another issue.

 

Yes the whole drive cycle. Many times.I'm assuming that the maf is being controlled. I will have to pin alot the boomslang and see what all is. From what I have read the others won't set until the cat sets do I guess Ill start working through that system first. Any way to tell if the sensors are out of whack easily?

 

update. the primary o2 sensor was crapped out. replaced it and all the rediness set. and it runs better too...