I just recently read that the PCM 'learns' our driving style and adapts to it. So I'm wondering if it's a good idea to disconnect the batteries on a somewhat-regular basis, or at the least when there is a switch to the winter or summer blend. Or when you replace a sensor. Thoughts?

 

First time I have seen someone ask this. I don't think that in something that need to be done on a regular basis. I also think when someone buys a used truck it would be a good idea to do this so the PCM can learn your dirving habbits. To tell you the truth, after I put my mods on I drive a little different.

Good question.

 

I have never heard of the PCM's learning our driving habits. Is there any truth to this? If so I need to reset the PCM on the EX every time I get in it...women drivers!!!

 

I think mine is done to old to learn,I have accused it of having alzheimers

 

Our diesels do not have an adaptive PCM. The adaptive shift strategies were only used on the the gas trucks.

 

To elaborate on clux's post....

Most manufacturers program certain "learning" capabilities into the PCM's programming. As far as the transmission is concerned, it's not really to "learn" a certain driving habit, but to accomplish a certain "feel" and speed of a shift. The PCM will actually measure the amount of time it takes to complete a shift. It uses various speed sensors to detect when a shift has taken place. The engineers decide how long it should take to perform a certain gearchange and use the line pressure control solenoid (EPC for Fords, PCS for GM) to attain the correct shift time. The throttle position is also used for this calculation so the shift takes the same amount of time (be it 1-2, 2-3, or 3-4) at any throttle position.

If the shift takes too long, the PCM will increase the line pressure during the shift. If it's too short, the opposite occurs. In all actuality, the system is there so that no matter the build/manufacturing tolerances in the individual clutch packs or servos, the shift will feel the same from one vehicle to the next. Obviously there are codes for out-of-range corrections that have to be made.

Another "learning" adaptive is fuel trim....but then again, it's a gasser thing too.

Oh, and I forgot that the adaptive strategy for the transmission can cause some havoc (on the GMs anyway) if you spend a lot of time towing or running empty and then do the opposite. If you tow constantly but then run empty, harsh shifts are the concern.

 

If I am not mistaken the clutch packs are the difference in the 4r100's between gasser and diesel.But is there another physical difference between them in light of the pcm assisted shift or learned shift points.

 

I asked this very same question to Jody at Smokin. He said: Yes, our PCMs do adapt and learn to some degree.

 

I would figure that the 4R100 for the 7.3 has an adaptive strategy, but I don't know whether it does or not. Clux may be more in the know there.....

 

BINGO!!! I knew I read it somewhere just recently, and on this sit too.

So they do "learn" - interesting. Aside from the safety reasons, I think that this may be a factor when changing a sensor. The directions tell you to disconnect the battery, etc. and that is for safety, but they may be counting on the effect of a 'memory reset' when you do disconnect power, and therefore allowing the PCM to relearn your habits based and all for the new sensor to 'integrate' itself. Interesting....

 

To elaborate on Rampages statement, Jody said that he spoke to the Ford engineers and they said that our trucks do adapt. Mine did for sure.

 

So, even something as simple as cleaning out the EBP tube and/or sensor, I'd think it would be prudent to disconnect the batteries for 30min at least, so that when you reconnect, it can take advantage right away of the different output. time to go unplug Nyx. Good thing I mainly use an external XM Radio setup!!

 

The PCM is definitely not adaptive as in "continuously variable".....but there are several preset fueling curves stored. The PCM will use the inputs saved in ROM to select the curve that most closely matches the drivers inputs.

That's my take on it anyways.