PCM Reset

[enjr44]

2002 SOHC 4L

From tech section. “NOTE: When battery voltage is removed from the engine control module (ECM) all learned values will be cleared and reset to predetermined values. When battery voltage is restored to the ECM, the vehicle may exhibit certain drivability concerns. It will be necessary to drive the vehicle to allow the ECM to relearn values for optimum drivability and performance.”

Questions: How long does this relearning take? What is the best driving profile to accomplish this? Also, does it ever stop adjusting values to maintain this “best drivability”? I am guessing that it never stops adjusting values to take into account sensor aging.

Thanks, Ed

 

[adsm08]

It is always trying to learn and adjust itself to wear and tear. Generally the initial drive cycle will be completed by accident at some point in the first week after the reset, but certain procedures can be done to speed it up.

The best thing I have found is to let it sit overnight with half a tank of fuel, start it up, then do a few minutes of stop and go, drive steady between 50 and 65 for five or ten minutes, then do a little more stop and go stuff. Usually gets most of the monitors to set. The EVAP monitor is usually the hardest to get set by driving and an 8-hour cold soak with the fuel level at the right spot will do that for you.

 

[Earl43P]

http://www.obd2.com/support/reprog/downloads/ford/ford-imset_procedure.pdf


http://www.obdii.com/drivecycleford.html

 

[RedRangerSTX]

Recently I ran into this issue where my Ranger (4.0L SOHC) was overdue for inspection and I could not get all of the drive cycles to complete after removing the battery for a repair (I would have waited until after the inspection in retrospect). In NY, all of the drive cycles but 1 need to be complete in order to pass the emissions portion of the inspection. My biggest problem was that for the EVAP cycle to run, the ambient air temp needs to be above 30F (and below 100F supposedly for those in warmer climates). Well, I live in NY and it was the middle of January, so +30F days were non-existent for several weeks. Finally I got a day where the weather hit a blistering 32F, and the EVAP cycle ran. The truck sat overnight, warmed up for maybe 5min, then I got right on the highway and held a steady 60-65mph. Supposedly keeping a steady throttle setting is helpful and it is supposed to be 20min or so of continuous driving without breaking/clutching. I did this, followed by maybe 10min of stop and go driving up a busy city street and it did the trick. Oh, and the tank should be between 1/4 and 3/4 full, or the EVAP test won't run either. Thats a pretty small window of opportunity with a 4.0L Ranger, lol. The other drive cycles seemed to complete relatively easily on their own. Good luck!

 

[enjr44]

So the bottom line is if code P1000 is still set the drive cycle has not been completed???

 

[RedRangerSTX]

There are various drive cycle tests that need to run (EVAP, 02 sensor circuit, etc.). The P1000 code means that at least 1 of those cycles has not yet completed. In my case, 1 cycle was not completed yet, but I was still able to get my truck inspected because the other cycles were complete. It still had a P1000 code at that time. It will remain on as a soft code (no CEL) until ALL cycles complete.

 

[adsm08]

So the bottom line is if code P1000 is still set the drive cycle has not been completed???

Yes. But not all the monitors have to be completed in one run. You will get it to complete the drive cycle eventually.