E39 540i intermittent power loss

[pezz]

Hi All,

I wonder if anyone could comment on the following problem that has developed on my 2000 540i touring auto... Over the past two months I have encountered an intermittent issue, where the car loses complete power for a split second as if someone removed a power terminal from the alternator/battery for a moment.

This causes complete electrical power cut, and the engine dies, the radio goes off then on, and dash lights come on as if key was just put into ignition. This has happened about 5 times now, and was once every month but have now seen it 3 times in three days.. Usually happens at low speed under light throttle or lifting off before coming to a halt.. but has happened when I was doing 70mph ish in the fast lane on the M1! (luckily could pull over into hard shoulder - and on that occasion, the engine did was running when I came to a halt, but there was a jerk before the power blip with dash lights coming on etc)

Possible candidates for problem causes I could think of so far, ignition switch (although I do not get the weird behaviour with vanity mirror, multifunction steering wheel or column adjust issues etc), loose earth somewhere. I have checked battery terminals having changed the battery within a couple of months or so and cannot recall whether I saw the problems prior to battery change...maybe once before?

Has anyone had any similar issues with their E39?

I appreciate any input/ideas anyone may have please...

Cheers

Derek

[pezz]

Any ideas at all from anyone..

Thanks again

Cheers

Derek

[rassi]

I would suspect (in no particular order) fuel pump dying, MAF sensor or CPS (cam position sensor).

[TheEnd]

I'd go with ignition switch, as you dash it turning off and restarting/ self testing

[pezz]

Thanks for the replies...

I think its leaning towards an electrical outage than a fuel/engine issue

I will look at the ignition switch asap..

I have been fortunate so far in managing to pull over when the problem happens
in order to restart the car esp as its auto..

[williamp]

The fact that you changed the batteyr would indicate to me that you should look here again. I've taken my battery out twice, and both times it was hard work installing it properly. So start with the bleeding obvious and go from there:

1) Is thre battery in the right position? Is it down far enough in its cubby hole, with the bolted bar accross the top, and the screw at the back inserted properly- ie can it move at all? its heavy, so yuo wont be able to move it by hand, but it should not move at all- in any direction.

2) Re-check the terminals, and the wires themselves. The +ve has lots of other wires coming from it- are all of these Ok, or kinked at all? Is the protective cover on the +ve termianal?

3) check terminals. Yes I know you did them, but try them again. Thay may look Ok, but if they are not tight then starting could be a problem...or they could vibrate loose on a journey, enough to break the circuit and cause a full electrical outage. take them off, and put them back opn again, making sure you tighten them.

I know its idiots stuff, but experience has told me that usually things like this are relatively simple. If not, then try the igntion barrell like others have said- but this might start costing you money. The things listed above are free!

Let us know how you get on.

[.Tim.]

Mine did that a few times, finally in the fast lane on the M25 in the rush hour. It turned out to be a fusible link somewhere on the firewall on the drivers side. The BMW warranty didn't cover it as it was a fuse, despite the fact that you can't reach it and it took hours for the garage to change it!

[Digger]

I had exactly this problem on my previous 2000 540i (posted on BMWLand about it) straight after I purchased it. Quite scary when it happens for no apparent reason, as you say a complete shutdown of the car! A prod of the +'ve terminal (key in ignition, but not turned) and electrics would flicker back on. Low speed as well, seemed worse when air temp lower. I could tell if it might possibly happen as the monitor screen would start to flicker! Only happened about 4 or 5 times but never cured it. Battery was replaced and all connections cleaned and tightened. Was also advised to check the bus-bar connections above the battery. Diagnostics suggested the ignition switch needed changing, so that was also swapped out. Monitor still flickered occasionally, so was never quite sure it was resolved even til the day I sold her.

If you find out the problem let us know?

Edited by Digger on Friday 3rd April 08:54

[pezz]

Thanks for the replies, they are all much appreciated.

I will definitely investigate the battery area again, although I did have a careful tug of the battery leads to see if anything would misbehave whilst the car was running but to no avail...

I now recall on one or two occassions that attempting to start the car with the key it hesitated to start turning over and on one occassion started paused then restarted to turn over before starting. Yesterday it cut out 3 times and so its getting progressively worked.

I did however make it safely to a friends garage who plugged in some diagnostics which showed the following errors:

114 Cam pos sensor bank 2
90 supply voltage pin 15
BD internal error instrument cluster
CF service interval

I will go and look up the code 90 shortly.

Interesting what you say Digger about having the problem with the same car, same year etc. I hope that I can nail it and cure it! Tim how long did it take before that fusible link problem was identified (before being changed)
did it show up on diagnostic?

Thanks again everyone

Cheers

Derek

[Killwilly]

pezz, Digger, wouldn't be the same car by any chance...............would it?

[Digger]

Killwilly said:

pezz, Digger, wouldn't be the same car by any chance...............would it?

Nope. Mine was a saloon. Having said that I have een half expecting a call from the new owner in case it cropped up again . . .

[pezz]

Yes I was about to give you a call digger :-)

I managed to get a new ignition switch from the dealer, surprisingly reasonable price of 34 GBP all in and in stock at few dealers. The person at the desk mentioned that their dealership were replacing approx 25 ignition switches a month a couple years back, so it is a well known issue.

Well I replaced the switch on Saturday. I did try testing various resistances across the pins to see if there was any difference between the old and new switches. so far, thankfully, I have seen any strange behaviour so far...but you know how it is with these things though, you get your hopes up so much such that the first few days or so of troublefree driving tend to make you assume it's all fixed ... so am keeping fingers crossed! (And staying out the fast lane in case the problem occurs again)

Thanks for input so far!

Edited by pezz on Monday 6th April 12:08

[williamp]

Well I hope you've sorted it

[pezz]

Just as I feared...

LAst week, just received the odd radio flash off and on...

The a few days ago the traction conrtol and I think ABS light flicked on a few times on deceleration .. but no engine cut out..until... YESTERDAY

The engine cut out 4 tmes on the way home.. and the dash lights flashed without complete cut out also. The frequency of incidents increasing as the journey went on so heat related maybe?

So... the problem seemed cured for 6 weeks and wondering if this means that the ignition switch has died again and if it has, is it down to some external electrical issue? Or, has me fiddling around in the ignition barrel area tightened up a connection which has worked itself loose again over the past 6 or so weeks.

In either case, I have gone back to my trusty 1.6 astra automatic for the time being.. Again I was fortunate that all the engine cut outs were at low speed and not in any dangerous situations/moves etc... I don't want to push my luck!

[pezz]

Are there immobiliser/transponder chips in the keys? Am wondering if a faulty kry could be causing this.

I will also find out about this fusible link.

Not too long ago as had issue where the car did not respond to the key fob and so I had to manually unlock with the key. This did not, however, trigger the central locking plus There was no flashin immobiliser/alarm lamp on the rear view mirror and turning the sidelights on did not work etc.. I had to shut the door and open it again for the car to come to life.. Also I noticed that the clock was then 10 minutes slow...

Something very odd is happening to this car!

Edited by pezz on Thursday 14th May 15:29

[TheEnd]

There are chips in the keys, but once the car starts, it doen't pay any attention to them.
Seeing ABS and ASC flash up could mean a voltage drop, as they are quite sensitive to it.

[Pentoman]

I suppose could be worth driving everywhere with lights on, heater on full, heated rear window etc all on to see if it makes it any worse? Or hook a meter up to the battery and watch the voltage?
When you changed the battery did it required jump starting at any point before then? Could have fried a relay or fuse or something then?

[pezz]

Thanks for the input, it was just a hunch about the keys as I know some keys have devices which could cause problems such as these.

The previous battery caught me out a couple times where it did not have enough power to start and I did get a jump once or twice. I dont recall whether the problems started before or after. I did wonder whether something was fried as a result of jumping. I will get some diag help tomorrow hopefully and will opefully see if i can get any more codes.

Thanks for the input.

Cheers

Derek

[Neomagic]

I'm sure I've read a very similar thread before somewhere, IIRC it was the battery terminals or the ignition switch at fault.

[Digger]

Neomagic said:

I'm sure I've read a very similar thread before somewhere, IIRC it was the battery terminals or the ignition switch at fault.

quite possibly mine on bmwland a while back?