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Won't Pass emissions "readiness codes"

13K views 3 replies 4 participants last post by  solstice1319 
#1 ·
Here is the problem

Had the battery disconnected during my recent work session and this inturn resets the OBDII MIL codes. I have driven about 300 miles and I have no DTC's , however the catalyst and EVP are showing incomplete all others are set to ok.

Your allowed only one readiness code not ready but it can't be the catalyst.

So the questions is does anyone know how many driving cycles etc. before the ready code for the catalyst is set to ok?
 
#2 ·
I think it takes a few days or a week of driving for it to reset itself, the computer needs to run all the cycles of daily driving and store them, then you will be ok, I think it's like ten or twenty driving cycles, but I'm not 100% sure.:yesnod:
 
#3 ·
It's not so much how much you drive, but how you drive that will allow those monitors to run. The catalyst monitor requires a very specific drive cycle to get it to run.

After a cold start, drive the car for at least 10 minutes and make sure it has come up to operating temp. Then, come to a complete stop for at least 2 minutes to make sure the test has time to run. It's important that during that stop that you do not let the vehicle creep. As soon as the vehicle speed is non-zero, the test is aborted. Doing this once should get the I/M monitor to report run and passed (assuming your cat is in good shape), but I would go through a couple more stops to give the test the opportunity to run a couple of more times for good measure.

If you're interested, what's happening during the stop is an intrusive test to measure the oxygen storage capability of the catalyst. The fuel management system will first go slightly lean for a specified amount of time, long enough to saturate the converter with oxygen. Then the fuel mixture goes slightly rich. At first, the excess fuel will be combined with the oxygen stored in the cat and the output of the rear O2 sensor will be unaffected. Once all the oxygen has been consumed, the rear O2 sensor will suddenly show a rich mixture. Exactly how long that takes tells you how much oxygen was stored, below a certain threshold and P0420 is set.

There's a lot going on in your car that most people don't know about.

As far as evap goes, it takes a bunch of cold start/long soak periods to get it to report. It uses the very slight vacuum created as the fuel in the tank cools while the car is sitting (typically overnight) to sense leaks in the fuel system as small as .020" (also referred to as EONV-Engine Off Natural Vacuum). The pessure changes it's looking for are so small, it takes a lot of trials before the algorithm is convinced there is no leak.
 
#4 ·
On 11/02/08 I had several codes active and it was time for my second safety inspection, so I got the codes cleared, drove the car about 50 miles, and went for the inspection.

Nope, too many "Not Readys." So I drove another 100 miles or so that day and the next and went back, only one Not Ready (Evap) so MariSOL passed.

I can't remember how many times I shut down and started the engine, but it wasn't very many times, maybe 4 or 5.

.
 
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