If that was the case wouldn't it be triggering a CEL then?

 

NO, his tune is taking care of the CEL, it's just not smart enough to fool the tester.

 

I just found this after some research.

Have you recently done either of these things?

 

I wonder if I am the only one notice that he is tuned by BYT aka backyard turbo aka nick. What is happening is he has a catless down pipe and nick tuned for that which he would turn off the cat warmup in the PCM which in return since the warm up is disable that test would be incomplete.

 

Kinda what I was saying when I stated his tune took care of a CEL lit on the dash by the tune. But the emission test is still looking for something that isn't there. I don't know what his tune entailed, but most of them tune to not light up a CEL for things like this.

 

Ahh, okay. That would cause the vehicle to fail, or more accurately, not complete the I/M Readiness Monitor Status test. Essentially, it looks for all of the components of the emissions control system, i.e. Oxygen Sensor, Catalytic Converter, EGR, etc. If it's unable to read the status of the cat, or any other component, the test won't complete. I could go into more explanation but it could get really long winded. Easier to look it up.

 

Might it also require a certain number of drive cycles to complete before it clears the Not Ready status?

 

It won't ever 'clear' the status if one of the items it's looking for is not there.

 

He could have the o2 turned back on and then just clear the codes when they come up. On a very rare occasion I throw a code, but usually only after the car has set a few day.

 

It isn't about codes, it's about the I/M readiness monitor.