ML 320 Keyless Entry Failure

[awaschka]

Hello to the board and I hope someone has an idea. I have a 2001 ML320 with remote keyless entry (presumed RF). It has worked fine for years but recently got erratic. I replaced the batteries in the remote and no help. I did the synchronization procedure in the manual, and there were some strange results. The sync procedure concludes with saying press either the lock, unlock or lilftgate button. Then check to see that all buttons are operational. Whichever button I press after the syncronization works, but then no more presses of any buttons work. The fact that each button works one time tells me that the key itself is good. I also tried disconnecting the vehicle battery for several minutes to try to reset any errant processors, with no success. Is there any other procedure, short of taking it to the dealer, I can try? Oh, and the second key is temporarily lost. Its in the house somewhere, but we can't find it so we can't try it.

Thanks,

Al