I live in California. We have to bring the vehicle in for emissions testing every two years. And a DTC will fail you automatically. I have found over the years that about every 3-4 years, the Check Engine light illuminates, and I consistently get a P0401 or P0402 Diagnostic Trouble Code. It is always the EGR tube and DPFE sensor. The solution for me has been to replace both parts, clear the DTCs, and then wait for the P1000 code to clear. The worst part is when I wait until the last minute to do it. I have to find time to go out on days off, to drive the car around. My daily commute is very short, and I can't simply go to work & back to complete the drive cycle. So I find myself taking roadtrips for no reason, to far off places I don't even want to go to.
I did try the instructions prescribed @
http://www.obdii.com/drivecycleford.html but I wasn't able to complete every step described, in the order described. Pretty easy to do if you have the use of a test track or race track. Very difficult to do in traffic. It's not as if everyone has plenty of wide open country roads, with no other cars, and no cops, right outside their front door. I live in The City. There is nowhere for me to "cruise at 40 MPH for up to 4 minutes", and this is the first driving step of the procedure. Even at night, the speed limit here is 25 MPH with stop signs and red lights for about 2 miles until I can get on the freeway. Then what? I either have to run all the stop signs and break the speed limit, or get on the freeway and drive at an unsafe speed which impedes traffic.
One other item to note is that I have a custom tune. Perhaps I am impatient. My emissions test is due and my registration expires in a few days. Earlier in the month, I replaced the EGR tube and DPFE sensor, cleared the DTC, and started driving the car around. I drove the car for about 3 weeks on my custom tune, and still had a P1000 DTC. Then I flashed the Powertrain Control Module back to my stock tune, and the drive cycle completed within a week.
I do not know if it is superstition. But I actually believe that my aftermarket tune may be written in such a way that it delays the completion of the drive cycle in a timely fashion. Perhaps the tune is written is such a way that it prohibits the PCM from being able to detect certain monitors. I have other vehicles with custom tunes, and those cars don't have the same issues, and are able to pass emissions testing with the custom tune installed. So the next obvious step is to wait until I pass the emissions test, get my new registration sticker, then flash the car with custom tune and monitor it to see how long it takes before the P1000 code goes away.
