bmw x5 2005 electrical problem

[skrewcop]

hi i recently bought a 2005 bmw x5 4.4i xdrive and when i start it in the cold canadian mornings(or evenings, here it's always cold lol) the 'trans failsafe prog' error shows up and the ABS light comes on and off and when it's on, the car loses power: the interior lights go a bit dimmer, the NAV system shuts down, the headlights switch off and so on...After like 20 mins if i leave the engine running, the abs light stops from coming on and off and everything comes back to normal...yesterday i even had an error saying something about suspension i cant remember what. Now the guy who sold it to me said he had replaced the battery and alternator a week before i bought it and he put them on himself. could this be because he did not do the job properly? i love this car so much and i want to fix it. thanks

[fmugur]

I would suspect the voltage is low when cold. The alternator brushes cannot make full contact at the beginning and after the brushes get warmed up then you get the full charging voltage.
Do a test. Enable the cluster to display the battery voltage and monitor it from the start to when everything is back to normal.

[David.X5]

The first time I fitted a new alternator on my 4.4, I had it rotated about 60 degrees (clockwise) out of place. It would occasionally trigger low voltage and other problems. For whatever reason, the bolts fit like that. Rotated it to the right place took the stress off the wires and moved them away from the frame rail. Perhaps something like that?

But, I would guess the previous owner had electrical issues and changed the battery and alternator hoping it would bandaid it long enough to sell it. The real problem may have yet to be found.

[skrewcop]

Thanks for you replies guys. Now something else is happening, there's a continuos buzzing sound in the cockpit coming from the nav area, no mather if the engine is on or off, the buzzing is always there. Now i'm no mechanic or electrician but i suspect that theres a short or some bad wiring connection that is draining the battery or something. And when i first start it it runs for like 5-10 mins and while im driving it, all the warning lights are starting to come on, which is an indicator that the battery is about to die, and i would pull over, turn the engine off and when i try to start it again, it wont cuz the battery is already dead. After i jump start it and leave it running, everything comes back to normal and the problem is gone for the rest of The day but the buzzing is always there. Any sugestions would be greately appreciated, thanks,

[bcredliner]

BMWs are very sensitive to low voltage. Yes, the issues could be caused by the battery and alternator install or one or the other could be defective. You can check the alternator output with either a multimeter connected to battery or by unlocking the cluster to do real time monitoring of the alternator. The battery is easily load tested at most auto parts stores. I would also check the battery to see if it amp ratings are equal to or greater than OEM battery.

[skrewcop]

How can i unlock the cluster? It's my first bmw i have no idea how to do it...so could it have anything to do with the cold too or it's all in my head. Thank you

[bcredliner]

This should help you unlock the cluster and check sitting voltage of the battery and if the alternator is working properly: ttps://www.youtube.com/watch?v=cXrWrkEqClU

Generally, it takes more amps to start an engine when it is cold. A good battery that has cold cranking amps of 720 or greater and a reserve capacity of 160 (BMW specs) or greater should start the vehicle except, in some cases, very extreme conditions.

[skrewcop]

Ok so i checked the voltage with the cluster when the engine was pretty warm and it wasn't that cold outside either. With the engine off it fluctuates between 12.1v to 11.9v sometimes and when i turn it on it's somewhere between 13,7-13.9v. These readings show when there's no warning light in the dasboard and no "trans. Failsafe. Progr". I checked the voltage this morning with the engine cold and -4*C outside and when i turned it on it went to trans failsafe program as it usualy does on the first start and as soon as the ABS light comes on, the voltage goes up to 16.9v and drops to 13.7-13.8v when the light dissapears and so on for 5 minutes. Could it be the voltage regulator or i'm having transmission issues? Thanks a lot

[g300d]

^looks like an over voltage situation is making your electronics act up.

Probably the voltage regulator.

Buzzing from the nav area could be the climate control sampler fan operating? It's behind the slats on the AC control panel, which is directly under the nav screen.

[Astrok]

I have the same issue. I have been chasing it for 8 months. Over voltage both times. I replaced my alternator with a factory rebuilt with regulator 6 months ago and everything was fine till 3 weeks ago. Car goes crazy lights trans fail safe nav goes off and on. My grandson describes car as having mental issues. This is my second issue intermittent over voltage. My son also had same over voltage failure on his X5. My lesson learned is this intermittent over voltage is more common then people think. Rebuilt alternators for these cars is issue because rebuilder does not pick it up. I am waiting for a new regulator from BMW rather than put in a warranty claim from rebuilder. I am hitting over 16 volts and as soon has that spike happens I get the BMW trifector of lights and car starts shuting down. When voltage goes back car will drive better Nav stays on and well as lights. PS removing. Alternator on 4.8 is a miserable thing to remove so I hate doing it again