There is a 9 step procedure in the manual to activate/deactivate the autolock feature. What happens if you follow that procedure? Do you get the horn chirp to confirm programming mode?

 

I'll be trying that in the morning, but I think the Smart Unlock not working is a bad sign.

 

I'd try disconnecting the negative battery cable for a minute and then plugging it back in. I replaced my battery recently, and although my locks worked fine it caused a hiccup with the ABS system. Disconnecting and reconnecting the battery corrected the problem.

 

Tried that. No change.

I have an appointment with the dealer for next Monday. I'll update sometime after that to report the result. I'm ~95% sure it's the SJB based on other Internet reports, but what's not clear is whether a reset/reprogram is sufficient or whether it needs to be replaced.

 

Dealer confirmed that it's the SJB. Needs to be replaced. Part on order.

Cautionary tale here... the SJB is apparently quite sensitive to voltage spikes, so be very careful connecting the 12V battery. I may even go so far as to recommend having a battery replacement done by your dealer as they would then be responsible if they blow the SJB.

Edit: I have come across another report from someone who claims there was a TSB on this (no number given) and that the cause isn't a voltage spike but from the low voltage condition when the battery dies. Anyone have a list of TSBs they could check?

 

Final update.

Had the Smart Junction Box replaced today and all is well (other than my wallet).

One final observation, for the sake of future readers of this thread. I've had two occasions when I've had the battery on my FEH run down; once when it was able to be recharged (though I suspect the writing was on the wall) and the more recent instance when the battery failed altogether. In both cases, the car began making a cycle of clicking noises from under the hood, much like a relay constantly cycling. In hindsight, what I think happens is that when the SJB experiences a low voltage condition, one or more of the relays it houses starts cycling. My conjecture is that this is hard on the relay and can lead to a SJB failure.

So my advice (based solely on the conjecture above) is that if your battery gets low and you start hearing a relay clicking, you may wish to pull the negative battery lead to avoid damage to the SJB.

 

Doesn't disconnecting the 12v battery cause the loss of the fuel trim and brake calibration settings? I thought the procedure was to backup the 12v bus with a 9v battery through the console power outlet before disconnecting the 12v battery. I even bought a tool to do that but haven't had to use it yet but probably will soon.

 

Yes, it does. But if you're about to replace the battery anyway...
I've done that before (not on my FEH) with mixed results. You have to make sure you turn off every discretionary load (dome light, radio, anything plugged into the power outlets) and even then it only works if the load from the engine electronics is low enough. That technique used to work quite well in the old days, before advanced electronics. These days it's more hit-or-miss.

Oh, and don't forget to use the non-switched outlet...

 

They sell a cord with a OBD-II connector at one end and a cigarette lighter adapter at the other for use with a jump pack which will handle anything. I have one but have never used it yet.

 

Is it like this one? http://www.ebay.com/itm/K-Tool-74308...ht_2385wt_1398

Makes sense that a little 9v battery wouldn't be able to handle this.

So, is it a problem if I don't preserve the memory when I replace the 12v battery? Or is using this device a good idea?