BimmerFest BMW Forum banner

1 - 7 of 7 Posts

·
Registered
Joined
·
42 Posts
Discussion Starter · #1 ·
Soon to go crazy over my "friend" since May, the E70 X5.

Will try to sum up as short as possible:
- A few weeks ago a red dynamic drive failure started to appear. It could be there one start and not the next. The first few days it appeared every start, but then it was working well again four out of five starts. I could feel the car "dive" more into roundabouts when the fault was present.

- Faults were:
DYNAMIC DRIVE (ARS) (ars_70) 4 faults
6276 Predrive check
5D5B Pressure build-up, front axle, faulty
6271 Predrive check
5D50 Supply, pressure sensor, front axle

- I sent the car to the dealership, they told me the valve block needed replacement a long with a broken front spring. I ordered the spring and a new valve block myself, and at the same time got ISTA+ up and running. Tried some troubleshooting with it, and found out that it was not possible to run a new initialization/start up procedure. Nor was it possible to zero out the front axle sensor, whilst the acc sensor and the rear sensor could be reset. I was able to read settings and also read values from both the front and the rear axle. After resetting the rear I had a stable 0 on the rear with the engine off, whilst front was fluctuating from -10 to +120 or so. Replacing the sensor (ie complete valve block in BMW world) seemed like a possible solution.

- I replaced the spring and drained the hydraulic system, was ready to put in the new block when I found out I would try to plug in the new wiring harness that followed the block, and try to reset the sensors. The new block was not connected to the hydraulics, but that should not matter at all since it was to be done with engine not running. Again same as on the old block, failed communication on the front axle sensor. And if I swapped the plugs, it failed on the other sensor. So then I swapped plugs on the old block, and the fault changed. So I concluded the sensor was OK after all, since I get communication error on four different sensors - two which was brand new. Also I feel quite certain that the wiring harness from the block to the inner front wheel fender connector is good, since I tried with two different.

- I measured the voltage at the sensor plugs, rear plug gives about 5V whilst the front plug gives about 4.8V. Not a significant difference, and seems like stable. ISTA+ claims the "measured" voltage at the sensor is 2,71V, which again says the sensors faulty, since it should be above 4.6V. However there are only three cables, and with my Fluke I get 4.8V, so the 2.7V measurement has to be in the control module, not actually at the sensor.

- Next thought were the control unit, so I got a used one from eBay, from a 2013 X6. Bolt on and responding, but same faults again!!

I don't know what to do now. ANY good suggestions are more than welcome! :dunno: :mad:
 

·
Registered
Joined
·
42 Posts
Discussion Starter · #2 ·
Some screenshots from ISTA.

I have also inspected the connectors and they look to be in excellent shape. No reason to believe anything fishy is going on there. Also it seems the wiring harness goes through the firewall right underneath the DD control module, but it also seems like the harness from the DD control module goes towards the center console. A little bit confused about that.

Bimmerfest is my last try before I surrender and deliver the car to the dealer again, and prepare to swipe my card without noticing the amount... :cry:
 

Attachments

·
Registered
Joined
·
317 Posts
Did you check the suspension level sensor located on both sides of the suspension look for a small D shape module with a small plastic arm attaching to a upper or lower control arm or to a strut not sure exactly where, it appears that its getting faulty readouts form the suspension level sensor, since its reading 0 in the rear and fluctuating on the front with engine off thus disabling the dynamic drive.

It looks like this part number 1
http://www.realoem.com/bmw/enUS/showparts?id=ZW03-USA-10-2010-E70N-BMW-X5_35dX&diagId=31_0796
 

·
Registered
Joined
·
42 Posts
Discussion Starter · #5 · (Edited)
I thought I had updated this thread, but apparantly not. :eeps:

Yes, I managed to fix it (that too...). It was a broken wire, probably only a few strands barely touching, that was why I was seeing just a slight voltage drop on one of them. After I measured while under load it dropped to 2.7V like ISTA said, at the valve. Just another normal BMW problem. During my 1,5 year ownership I encountered three different broken wires (only inside the insulation and somewhere around the firewall, no visible damages), causing problems to dynamic drive, wheel speed sensor and the air suspension. I soldered in new wires and it was all good. Apparantly the wiring looms must have been laid too tight and over time the wires start breaking inside the insulation. I have had tons of BMWs over the years, but this was the first american built, and first time I have ever seen faults like that - which should never happen. I was so impressed with the quality I sold it and bought an american made Tesla Model X instead. :rofl:
 

·
Resident Curmudgeon
Joined
·
24,322 Posts
what year was that? Wonder if it was an early mfg process?
 
1 - 7 of 7 Posts
Top