Disconnecting the battery

[andyny]

The safe and general rule is to disconnect the - battery term before doing electrical work. I noticed though that this seems to be an issue (and it may be more issues). Here is one problem I know is for a least 2002-2005 ELANTRA with Auto.

DESCRIPTION:

The transaxle control module (TCM) has internal logic that allows the TCM to compensate for mechanical tolerance changeswhich may occur during the life of the transaxle due to normal wear.If battery power is disconnected from the TCM, the adaptive learningis cancelled.


Whenever battery power is disconnected from the TCM or a new transaxle is installed, follow the procedure below to restoreadaptive learning:

NOTE
If adaptive learning is not performed, the transaxle shift quality may be affected.

ADAPTIVE LEARNING PROCEDURE:
Attach a Hi-Scan Pro and select "Automatic Transaxle" menu, "Current Data" menuand "Trans Temp. Sensor".

Drive the vehicle until the ATF temperature is above50°C or 122°F (adaptive learning does not occur below this temperature).

Accelerate the vehicle through several 1-2-3-4 upshifts and 4-3-2-1 downshifts at light and medium throttle openings untilshift flare and shift shock no longer occur.

NOTE
Because of the internal transaxle design, adaptive learning for the 2-3 shift takes longer than the 1-2, or 3-4 shifts.

I certainly do not want to deal with this when I am simply installing some fog lights soon. I think may if a make a 12V source with clips and atttach it to the battery terminals cables so no 12V source is lost when I disconnect would solve this. Actually this seems to be an issue that was in cars when they first got airbags.

ANY ADVICE OUT THERE.

[getfuzzd]

you can also hook a 9V to the cigarette lighter in most cars to save the memory(ies)
I'm not sure if the XD(2) is a switched lighter outlet or not, though...

[andyny]

I stopped by the dealer today and talked to a mechanic. He said that if you disconnect the battery, when you restart it don't drive it yet. Let it warm up and you hear the fans go and and off a few times. Then drive slowly around, and then drive so it goes through al the shifts for a while, and it will relearn without the resetting the electronics. without warming it up it will slip and feel like ****. The key was to do it when the engine was warmed up. I asked over and over about the tech note and I do believe what this guy told me. He also did not recommend the adding a battery voltage to keep the power when the battery gets removed. He also though it was not a big thrill to lossen the nuts and slip the connectors on without disconnecting the battery (at risk of shock of course).