OK, I know various things have been bandied about here, but on re-reading the manual RE: reprogramming the remote, I'm questioning some statements.
Seems to be a school of thought that you can only carry out the reprogramming procedure 4 times in the life of the car, and that possibly a friendly Mits service man armed with a MUT can reset it. BUT... I'm now reading the manual as saying that you can only program 4 keys at a time, and that there isn't actually any TOTAL limit?
Can anyone say with authority which is the correct answer? Is there a total limit or not? Reason being our new TL has stopped responding to the remote. Battery reads fine and connections seem fine, but I may pull the battery do some touch-up soldering to be sure, but I don't want to "waste" a programming cycle, as we only have the one remote and would like at some time in the near future to get another, which would mean another programming cycle (programming both remotes at once). Not knowing how many times the car's already had the procedure done, I want to know for sure that there's no limit before proceding.

Oh, while I'm here, on a related note: is the key completely waterproof? ie. can I take it surfing without risk of damage to the RFID system?

PPS. anyone got a spare remote lying around cheap?

On my TJII i've reprogrammed the remote at least 20 times because the battery keeps losing contact, there definitely isn't a limit of 4.

Oh, while I'm here, on a related note: is the key completely waterproof? ie. can I take it surfing without risk of damage to the RFID system?

The key is sealed but the metal might corrode from the salt water so a good idea to rinse it off under a tap after taking a dip.

The remote may have a loose battery. Take it off the keyring, and gently stick a butterknife (or flat blade screwdriver) in the crack around the edge where it goes on the keyring. Gently twist (look closely to see that it is coming apart and not just mangling the plastic, if it mangles try a different implement)
Have a very close look at the metal tabs that come down out the black plastic battery holder, they may have cracked and need re-soldering and lost electrical contact if its been dropped too many times/too hard. There's a DIY here somewhere on replacing the battery and holder with a bigger battery permanantly attached to the board.

Seems to be a school of thought that you can only carry out the reprogramming procedure 4 times in the life of the car...

I too have heard this school of thought, but I haven't seen any actual evidence to say theres a limit to the number of times you can enter programming mode. FYI, I have had my KF Xi in programming mode more than 4 times.


Battery reads fine...

Does this mean you checked the battery with the multimeter?
Even if the battery seems fine when checked with a multimeter, it could still be stuffed -- first port of call is to replace battery (before cracking out the soldering iron).

Regarding touch up soldering... bad idea. Proper method would be to remove old solder with desoldering braid and resolder. If you just try to 'touch up' existing solder, all you will end up with is a weak ineffective solder joint that will only given the illusion that it appears OK.

I had a huge soldering iron and no wick, it was the best I could do at the time =( just got to make sure I don't drop it.

edit: I've also had my car battery go flat a few times and be disconnected a lot, I should be way over my 4 times limit. I think the limit is for how many remotes can be programmed to the one car at one time, and I think its stated as 4 but some people have only been able to get 3 in?

You can only have 3 remotes programmed at once

Tried it with some mates at school when my remote died:D

I had pulled it apart a few times last night and inspected all joints and holder legs, all appeared fine but could possibly be a dry solder joint somewhere. Used a multimeter at the two points at back of the PCB and read at 3+V, so also appeared that the power is getting to the board, but then again it only needs one moment of non-power to lose it's bind.
I've actually fixed one of these for a friend previously and re-bound it to their car. Battery holder had completely separated from the PCB.
I might track down some spare CR2032 batteries anyway, just in case.

Have a read of this

http://martybugs.net/magna/remote.cgi

For your information there is no total limit to how many times you can do remote programming because i did 10 times in a year.