bcredliner-
I was driving the other day when I heard a bing noise come from the dash.. The 4x4 light came on, and a few moments later another bing noise and the ABS and a red Exclamation light came on..
It happens usually after 10-15 mins of driving and then stays on until I stop and turn the car off for a period I time... Then it's off again for a bit but comes back on after a few mins...
I was thinking maybe the ABS sensors? But then why wouldn't it be there from the start.
Cheers

What month/year is your X5? I am not familiar with the diesels, but the the transfer case gear is only seen on later gas models. If you have an earlier one, that may be something that could be eliminated (or move higher on the list).

The wheel speed sensors can be intermittent for a variety of reasons. Heat can open a circuit that is close to total failure, etc.

The codes should be stored until cleared and those can be seen with some software. Of course, it is always better to be able to diagnose it when it is making the actual fault.

Be aware that when those lights are on, the ABS and DSC is disabled. You would have normal braking, but not the computerized functions.

The DSC computer module itself can go bad (an internal connection pops off) - this is what happened to mine - in the US there are a few companies that will recondition it and return it to you. Don't know about where you are. If you get a new one (about US$400) then it needs to be coded to the VIN in the car - something a dealer or well equipment BMW shop can do or someone very good with the eBay software.

Given your symptoms I would lean towards the module being bad. After a while of driving the engine bay temps heat up the module and it fails. I just had to have mine repaired due to that.

You could try turning on your ignition but not starting the engine, and hold a hair dryer to the DSC/abs module. Get a little heat in it and see if the lights come on, if they do, it's probably the module. But really you should try to get the software to scan codes. Its less than $100aud I believe.

Just to make this more exciting, a bad module can generate a lot of codes that point in other directions (like bad wheel speed sensors) when it is really the module. Mine tricked me into replacing two wheel speed sensors before I wised up... There are whole threads here dedicated to trying to sort out the module or something else, depending on the codes you get.

I read your initial description and this clarification that it is not what I would call intermittent so any troubleshooting without knowing codes is a shot in the dark.

I can't add anything that hasn't already been said:

Best course of action is to read the codes. I would take it to a well recommended BMW indy shop to get it done sooner than later because of the safety systems that are now inactive. I wouldn't wait to get and learn how to use a diagnostic tool, especially not the BMW software package. I am all for common sense troubleshooting but in this case I would want the codes to provide an indication of where to start.

Yeah your right, I might just have to find a shop ASAP instead of driving it with the safety systems inactive.. It started as intermittent the first few times as it was only happening every 2nd or 3rd drive.. but it's quickly became every drive..
I'm in New South Wales Australia and I'm not sure what u mean by an "Indy shop"?

The cars a 2005 3.0 turbo diesel but not sure of the month right now as I'm at work and can't check the cars papers..

Cheers guys I've got an idea of what could be wrong now and how to go about finding the fault my self.. I've order the scanner but like you've said it might be best to chase up a shop ASAP as it's probably not the safest X5 on the road at the moment

"Indy shop" means an independent mechanic who specializes in BMW (and one hopes has BMW experience and the specialized code readers, etc) as opposed to an official BMW dealer or a general mechanic who works on everything but doesn't have any of the brand-specific tools (or knowledge).

Your transfer should have an actuator on it, so the common failure of the actuator gear should remain a possibility.

In that case it probably isn't the abs module. I am not sure about the AUD vehicles, but in the US it seems only the prefacelift models have the module issues.

Cheers man, that clears a lot up haha.
Yeah I think I know a place that specialises in European vehicles that I'll ask and see if they can help me out.
Thanks again

Got a quote but it seems like they're trying to take advantage of the situation.. I've ordered the scanner but it won't get here until around 25th of Feb :/
I'm definately leaning towards the ABS module due to the fact that the lights seem to stay off for longer when it's colder weather.. But after 15mins or so "bing" and there they are again