Thanks for the reply. I did not clean the battery posts but do not see any corrosion on them. Certainly worth a try...and much cheaper then a new battery! I just don’t want to spend too much getting this fixed, the Rover has 260,000 miles on it and continues to run strong but is only worth a few thousand bucks.
I noted your comment re cleaning the battery posts.
Given that your 3 was OK prior to being parked for a month, I do not think there is much wrong with it however finding the problem, well that is a big deal.
Re the negative battery cable, it is a short little thing; you might want to disconnect the end where it connects to the body and just shine up that connection area. I recall that as a matter of maintenance, I replaced my negative battery cable as apparently it can suffer internal corrosion problems. My view was that I wasted my money buying a new factory cable and that nothing was wrong with the cable, but just undoing the fender end and reconnecting was probably a good idea. Incidentally, I did not have an problem prior to or after the negative battery cable change, it was just a preventative maintenance thing.
Re charging your battery, for me, it takes at least a week of nights for my CTEK 3 amp maintainer to get my H7 Interstate up to where the CTEK is happy with the state of charge.
What I am saying is that a single day charge, while the engine starts OK, may not make the computers happy.
I think what happens when the 3 sits is that the battery discharges and the 5 VDC computer systems start to feel starved of amps. I think their internal voltage convertors are not very good and require closer to 13VDC input to yield a clean 5VDC current to the chips.
What then happens is that as the battery voltage drops, various of the software modules quit, much like you tripped over the power cord on a conventional desktop computer and caused a crash.
Getting a desktop to restart without corrupted files is not a given. I think something similar happens to our 3's. Remember, they are mobile computers first, and secondarily the worlds best 4x4.
If you had access to a BlackBox or Gap code reader, you could erase most or all of the error messages and effectively un-corrupt the software. This is in part what the Hard Reset does, but only to some of the software; mostly the entertainment system, and not necessarily the software within the engine module.
I find that when I erase all my error codes with my BlackBox, that if there is a real problem, that initially all is good and then within a few minutes or hours, the problems/codes will reappear. I regard that as good news as while the error messages will not actually tell me where a problem is, at least I know I probably have a real problem and not just software corruption.
That is the thing to remember about codes, there is no software code anywhere that says there is corrosion at the ground cable or that a conductor is broken. Instead, the software tries to find some existing code it already has and spits that out instead.
Incidentally while most of the Land Rover dealers are quite good, there are a number of independents who now have Land Rover related code readers. For the most part, the Land Rover code is Ford generated, and hence not so foreign any longer.
For whatever reason, Audi guys are usually not afraid of Land Rover - must be because BMW did the original design of the 3 before Ford took over.