i think while replacing the hydropump they may have bumped the ground wire and this would have appeared to fix problems.
X5's have a ground/negative just like 540's you know
Navigation issues still remain...
Having an accident has nothing to do with corrosion on ground terminals.

I dont think the problem has been fixed properly at all.

Please refrain from being a rude forum member when all i was trying to do was actually steer the OP member in the right direction...sorry for trying to be helpful and pass on experience and information for which this entire board is here for!!!