getting random warnings on 2000 740il

Suggest that you get a fault read-out either from an independent or BMW dealer - cost about £40 or $80.................

Unfortunately - yes - if you saw a spark when you connected the jumper - it may have caused a high-voltage pulse through the electrical system.

One question - have you replaced the battery? BMWs are notorious for having all sorts of bizarre electronic problems when the battery is going bad.

If you have - unfortunately then the other scenario may be the cause of your problems.

BTW - what warning light is coming on? If it's the one that looks like a battery - you have a bad alternator.. which could be the reason you needed the jump start to begin with.

The fix involves replacing the effected components. Depending on which components are involved - the new replacement cost may exceed the value of your 740i. Used components/modules are certainly an option - but they may have to be re-coded by a dealer with the GT1 diagnostics system for them to work in your car (many of them are vehicle specific - right down to the VIN#.)

I'd first check the voltage at the battery with the engine running - it should be 13.8 near enough spot on. 'Trans fail' is often the first indication of the voltage being low. Be worth having the battery checked too - some say a faulty one can cause this even although the running voltage appears normal.

Do - or have these done - first, before getting involved in expensive engine diagnostics etc. Simple things first. ;-)

this is normally a sign of low volts from your battery, and er it went flat - perhaps it is dud and time to replace it?

I had an '01 750 ... the 12 cylinder one. It had two batteries ... one to start the car and the other to run all the electronics. Both went dead after the car sat in storage for 6 months. Expensive dubbers to replace at BMW.

RCE

i checked the voltage and it says 12.3....is that too low??

If you followed the instructions in my post - above - what do you think?

Dave,

I'm not an auto mechanic, although I do play one at home with the missus on occasion, but I would say that 12.3 volts is significantly below 13.8 volts.

What do I win?

A gallon of single malt. Due to air freight regs the liquid contents can't be sent, though.

I have heard of Ford's running on ethanol, but BMW's on malt whisky? Anyway don't the Scots put water in it?

No because the surface voltage of a 12V lead acid battery can be anything from

Which part of 'with the engine running' escaped you?