Engine fail safe light came on and idle is now rough, gas pedal not responding
 

So before I left for vacation 2 weeks ago I had my coolant resiviour crack in the car wash drive through. Luckily the car did not overheat as I saw the steam coming out and shut her down. I was able to get the part from the BMW dealer 3miles down the rd and replace it on the side of the road.
Today I came back, the truck was dead as a door nail. Battery was compeltely drained. I put her on my charger for about 3hrs on a 10 amp charge and it started right up. I decided to take the truck food shopping, it ran perfect, dead center on the temp gauage. When I pulled into my driveway I revved the engine a few times just to make sure she sounded good and all was clear, then boom, engine fail safe prog....

Any ideas? I decided to disconnect the battery and put the charger on the battery directly on a 2 amp charge which I will leave on overnight. Just in case the low battery was causing any issues.

Will the code clear with the battery disconnected overnight or will I need to bring it somewhere to have it cleared? If the same thing happens tomorrow I am stuck since the truck is not drivable...

Having a battery like that can wreak havoc on the E53's. Place the battery on a trickle charge overnight like you are doing and have the battery tested. If the battery is over 5 years old, it is probably shot anyways and is begging you to put in a new one.

+2 what twinturbo said.

Engine failsafe will clear from cluster but stay in the computer. You shouldn't see it on the cluster though if it was the battery that caused this.

Thanks, the battery is just shy of 2yrs old now, from Autozone. I guess I can take it there and ask for a replacement under their warranty to avoid any future issues. I will let you know how I make out tomorrow.

There was a thread somewhere about batteries from AutoZone not being able to keep up with demand. Even bosch brand from Pepboys had problems. Seems like the only way is to use OEM from BMW or I think Interstate???? or some well known manufacturer makes the batteries for BMW.

Well after more than 12hrs of 10amp charging I still have the same issue...As soon as I reconnected the battery and started the truck it was idlding rough (like a 69 camaro with a lumpy cam) and engine fail safe came back on...I am now stuck in my driveway

Could be alternator too. Unlock your OBC and check the voltage.

Thanks for the continue feedback. I just checked with a DVM, I have 12.5volts not running and 13.8volts when running so it looks like the alternator is outputting as expected. I also took apart the air intake hoses to check for any cracks, and lubricated the MAF sensor connector and re-assembled with the same results.

One interesting test I did was to start the truck with the MAF sensor connector disconnected and it did the same exact thing. I am wondering if the MAF has failed?

get the codes scanned. You are at that point now.

If I remember correctly Douglas? makes the OEM batteries. They do not last too long for some reason.
My Exide is almost 8 years old now. I have heard good things about Interstate but never tried them.
I bought a K-Mart battery for one of my vehicles a long time ago. (20 years.) It failed after 5 years but it only cost me $20 to replace it thanks to their pro-rated warranty. It was still in the vehicle when I sold it about 5 years after I replaced it.