Long story short. Did head gaskets on our new-to-us Disco II. Cleared codes. Need to smog it to register it properly. Catalytic and EVAP readiness were super tough to get rid of, even attempting to follow the driving routine I found online. Today, of course, a MIL pops up. I plug in my scanner and it's a p0455. I'm fairly certain the gas cap didn't seal properly, as I took mental note of it when I filled up the day before. At the same time, after 200 miles or so of driving, I finally see that the readiness passed...damn it.

Assuming it's the cap...will this code clear on its own? I really do not want to clear it and go through the readiness process again. If so, how long does it take on these vehicles?

 

Must be one of those questions that doesn't have a clear answer. I'll drive it around through Friday and see if it clears itself...

 

It takes on average 40 drive cycles of proper operation for a code to go from current to stored, or pending as the ultraguage like to call it. A drive cycle consist of cold start, getting up to temperature, a predetermined amount of drive time at 55mph,(the cars i deal with are 10 miles) and then cool down. that is one drive cycle.

It would probably be faster for you make sure the cap seals, clear the codes and drive the vehicle on a few longer trips to get the readiness monitors back up and running.

 

In CA it will clear without the evaporative being ready.

 

Great info. Thank you.

Yeah, was aware. When I say it passed readiness, I mean that the Cat check was complete. Evap was still pending.