River1

With our trucks, what is and isn't effected by disconnecting the battery? An internet search will deliver disconnecting the battery will cause the "Check Engine Light" to come on and also that it will turn off the "CEL.". It will go on because the emission information in the adaptive memory is cleared. This causes the sensors to lose their reference. Also to be found, because that same information is cleared, the "CEL" will go out because disconnecting the battery clears the codes. Which is it and this is just one example of the variety of information there is.

I haven't found anywhere online a general outline of what is effected or what should be expected from disconnecting the battery. Nothing I consider reliable anyway. Can anyone explain what is "standard," so something non-standard can be identified? TIA

Tackle

This should give you the information you're after.

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

jprevat

iTrader: (1)

The only electrical circuit that shouldnt be affected is the keep alive memory or KAM. A fault p1633 shows up when voltage drops below 11.5 (iirc). If it is a soft set, such as a battery disconnect, the code will clear itself.

River1

For my question this is a bit over the top. It's a generic question about what effect does disconnecting the battery have? I wasn't looking to take it any farther then that. The "CEL" example was used as a non-specific reference to how scattered the information on the web can be.

But on a completely different topic this was great. Thanks. Long story and not important here but I was looking for the cycling rates and ranges along with the refresh rates for Ford control modules. This led to it and more. It saved a lot of time so again, thank you.

BTW, you're a Ford mechanic aren't you? Have you ever missed a step and have to start all over?

Tackle

No I'm not a mechanic. When you disconnect the battery, it clears stored codes from the CEL being on and resets the readiness tests described in the link. Your CEL shouldn't come on except momentarily when you start the truck.

In a couple days of driving, you'll typically perform all the steps in the list, putting all sensors in a ready state providing your truck doesn't have issues with any sensors. If you have emissions testing and put in a new battery the day you need to get tested, you can use the list to complete the cycles. You don't need to go in order.

A cheap obd2 scanner can show the status. I don't have the ranges for you though. Is there a problem you're trying to solve or just looking to gain some knowledge?

River1

What do you mean by "soft set?" I don't want to "assume" anything about it.

What actually prompted the question wasn't fault codes. I'm curious about the so called "adaptive learning," done by various modules. Your mentioning "KAM" may be what I was after. I'm considering some things I wouldn't want lost because the battery was disconnected, but I also don't want to take away the ability for someone to learn with hard wired or inflexible programming. I Hope that makes sense.

River1

Always glad to gain some knowledge but this is mostly problem solving. Proactive problem solving though in the form of a young teenager and her truck. My response to jprevat while you were writing may help explain.

jprevat

iTrader: (1)

If it was a soft set then the KAM circuit has regained power from a temporary loss. If it is a hard set then the KAM circuit has lost power. More than likely due to wiring or a pcm problem.