Not your typical XDrive Problem (Car wont move unless abs module unplugged)

[busted]

Hey guys,
Vehicle is a 2012 x5 35i

I posted this on other forums but feedback was not helpful. I fortunately happened to stumble upon this site specifically for X models, hoping someone has had a similar issue or could help. I am going to be as detailed as possible. So, here it goes.

A week ago, I parked the car, came back and upon starting the car, i got DSC and 4x4 on the dash (only these, no park or abs). I pulled out of my driveway, and once i put the car into gear, my car literally would not move faster than human walking speed. I tried flooring it, and when i did this, the dsc light would flicker (like it was "doing it's job). No feeling of abs pulse (although i did get this when i reversed). THe car just didn't want to move.

Pulled the car into my garage, and plugged in my scanner (a very fancy snap-on that is capable of reading everything). I got code 5dec (transfer case malfunction). I deleted this code, but it immediately came back once i tried to drive the car again.

Fast forward to a few days later when i decided to dig in to the car myself as i couldn't drive it to the nearest indy and dealer was backed for 3 weeks. I removed the abs module connector to see if there was anything funky there, and there wasn't. I left it unplugged, and tried to drive the car that way, and it worked. I was now able to drive the car, granted now I had abs, park, dsc, 4x4, airbag, etc lights on. No odd noises, no driving issues, nothing. Also, My speedometer is way off (it reads 35mph when I am going close to 60mph)

Now, I find it hard to believe my transfer case is bad, especially since its not making any grinding/howling noises. A little more digging in, and i found if i plug the abs module back in, but remove one of the fuses, I get the same results as leaving the abs module unplugged, except now my speedometer works, and I am able to drive around while reading live data from the abs module.

I decided to go to my Land Rover Indy, as all the BMW guys were backed up. He put the car on the lift and started to inspect. He spun the right rear wheel and it spun the left rear wheel in the opposite direction which is what it's supposed to do. Then he went to spin the front right wheel, and it did not spin the front left wheel? He said he is not sure about these awd bimmers, but on a rover, it will spin the other wheel. He exposed the front driveshaft, and if he spins either wheel, it will spin the front driveshaft. Now, we do have that 5dec code, which according to his autologic scanner, means DEC 5dec - clutch gearbox-ECU: clutch temporary () closed. rear-wheel drive!

So, he is not sure if this is hard programmed to act the way it is currently, or if there is a mechanical malfunction.

Here is another important piece of info, I plugged my scanner in, and while driving, I get speed readings from my rear wheel speed sensors, but my fronts remain at 0mph. This is with all fuses back in and module plugged in stuck in the 3mph speed limit. I find it hard to believe both of my front speed sensors went out at the same time.


Soooo, with all this info, what are your guys thoughts on this. Could it be the abs module. a sensor? etc.

THings I have done:

Checked battery, it is fine. Removed the transfer case actuator motor, and that is fine as well (it is the new style without the gears).

[busted]

Bump,

Here's hoping someone will chime in

[ninja_zx11]

Not sure if you have tried removing the transfer case servo motor electrical plug? Try to drive with plug removed.

[busted]

Hey Ninja. Thanks for the response.

We checked all 4 speed sensors, and I removed the transfer case actuator to inspect it. I read a lot about these actuators gears going bad, but those were on earlier years with the worm drive and gear. This is the updated brush setup, and it looked in top shape.

We had to remove the transfer case support cradle; but fortunately, i was at my long time trusted rover tech's shop, and with a lift it was only about 30 minutes. Are you saying I should leave the motor unplugged? I'd imagine this would quickly throw me into failsafe.

I reread my post, and thought I would clarify on one point. with the abs module disconnected, my speedometer is inoperable; but with the module plugged back in, my speedo readings are about 25mph slower than it should be.

AHHHHHHH, so many different issues! I'm going crazy with all this research and thinking.

[ninja_zx11]

Originally Posted by busted

Hey Ninja. Thanks for the response.

We checked all 4 speed sensors, and I removed the transfer case actuator to inspect it. I read a lot about these actuators gears going bad, but those were on earlier years with the worm drive and gear. This is the updated brush setup, and it looked in top shape.

We had to remove the transfer case support cradle; but fortunately, i was at my long time trusted rover tech's shop, and with a lift it was only about 30 minutes. Are you saying I should leave the motor unplugged? I'd imagine this would quickly throw me into failsafe.

I reread my post, and thought I would clarify on one point. with the abs module disconnected, my speedometer is inoperable; but with the module plugged back in, my speedo readings are about 25mph slower than it should be.

AHHHHHHH, so many different issues! I'm going crazy with all this research and thinking.

This code 5dec translates to 2,possible faults according to ISTA.One says transfer case malfunction and second cause could be "wheel speed sensor rear left-short circuit to positive.Better to scan your car with ISTA.

[busted]

Hey ninja,

I can't remember what the name of the site was, but my tech has a subscription to it and plugged the code in along with the make and model. he did tell me the second variation of the code which was also a wheel speed sensor, but said no way it was because I would also get an ABS light, so i left that bit of info out.

The more I'm thinking about it, I'm leaning towards the issue being the dsc/abs module. Main reason for this is that I have no readings from both of the front wheel speed sensors. I'll do a little more digging in before i bite the bullet, but that is where my gut is pointing me towards.

[ninja_zx11]

Sorry can't help you further as I have no expertise.ISTA can guide you by presenting test plans according to the fault code.

[busted]

Thank you for all your help. I already appreciate it, I'm currently trying to find info on ISTA, thanks for leading me in that direction.

Have a great Thanksgiving.

[bawareca]

Yeah, this problem requires ISTA. If you are close to LA I can help.

[busted]

First off, Happy thanksgiving everyone.

Bawareca, I am not near L.A, but i do appreciate the offer. I have been looking into ISTA, it seems like it is bmw's diagnostic tool setup. Is it really that effective? I have a snap on solus ultra and my friend has the Launch GDS. Also, my Rover mechanic friend has Autologic (these aren't your typical cheap scanners).

Bawareca, I have seen your name pop up on a lot of forums and you seem to know your stuff really well. Mind if i pick your brain a bit?

- Do you know if with the car on the lift, If i spin the front right wheel by hand, should the left front wheel also spin as does in every 4x4 car? This car does not spin its counter wheel on the front, but if i spin the rear left wheel, the rear right will spin.

- Getting no codes for front wheel speed sensors, however on live data, both fronts stay at 0mph, while both rears will report speed? anything other than the abs module that would be effecting this?

-Speedometer reading is drastically reporting slower than actual speed. Any sensor that would cause this?

- If a mechanical failure is present (transfer case/differential/etc), i would imagine that i would be getting weird noises. Have you ever seen a case where a diff or transfer case would go bad and not seem evident?

Thanks again to all who have helped.