[Marty in NY]

Originally Posted by Captain Hook

Thanks frisbeeguy. We did get a refurbished TC the other day and cleaned it up nicely. We also found an independent mechanic who isn't thrilled about putting it in but said he'd do what we ask. We haven't moved on that yet though.

Marty in NY: Here are the codes the mechanic gave us before he unplugged the transfer case so that the vehicle is at least driveable (though X-drive and the speedometer don't work after he disconnected it...)

Dynamic Stability Control, 2 faults
480A90 DSC: Roller brake tester mode active
48068C Transfer box: Temporary fault, temperature

Integrated Chassis Management, 1 fault
(ICMQL) (ICM_25)
D02C67 DSC interface (status, DSC stabilisation, 47.1.2): signal invalid

Digital Engine Electronics, 1 fault
(Motor) (MSV90)
CD9304 BSD data bus Communications fault

Transfer Box (LMV) (LMV_01), 1 fault
440117 Transfer box (VTG): All-wheel drive transfer box temporarily shut down - clutch protection

I know from you perspective this is looking like a Xfer case issue, and maybe it is but there are a few things you should diagnose first. Your symptoms are almost identical to the ones I had, like 95% the same. I did not have the Xfer case codes though but the Xfer case may simply be a victim of whatever the real root cause is.

Go here --> https://bmwfault.codes/ and plug in your engine number and then all your codes, one by one and screen copy or print out the results and then start looking for the issue systematically. Example: Wheel Speed Sensor - inspect the condition of the cable from the sensor to its connection point. If that looks ok, pull the sensors and inspect the sensor end, it should look new except for maybe being dirty, just clean the end with a wet rag. Then look into the hole it goes into and see if there are any obstructions, you may need a flashlight and small mirror to do that. BTW, all my sensors looked just fine, so I started swapping them and the error codes followed the swap and that is how I knew I had at least one bad sensor, turned out I had two that failed at the same time and am still puzzled by that.

The Xfer case, like many other smart assemblies on a BMW have a self protection mode built in that will, upon seeing bad input, either disable themselves or go into a limp mode. So if perhaps you have a bad wheel speed sensor and it was causing the Xfer case to freak out and over heat, the Xfer case will first throw a code and then start protecting itself against destruction by either shutting down, going off line or disabling the 4 wheel aspect and going into only a two wheel drive mode. Once it cools down, it goes back to normal (self heals) until you drive it and it sees the same bad input and starts to over heat and the cycle repeats.

In terms of the Wheel Speed Sensor, this may have a few different failure modes with each mode causing different symptoms. For example: it may still work but intermittently or it may send a signal that spoofs the CPU into thinking that wheel is turning in the wrong direction or it simply may not be sending any signal at all. There are a lot of functions that depend on the Wheel Speed Sensor's output. Looks like you ready my previous posts so no sense in just repeating it here.

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Here is how you read the BMW Fault Code Lookup page.. ..

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[Captain Hook]

Awesome Marty! Wow you put a lot into that response. Thanks. I'll start digging on all that. Two quick things before I do...

1. I'm a total novice at BMW's. Grew up on old Volvos and morphed into Japanese models, so please forgive the question: How do I look up my engine type? This is part of looking for codes in the link you sent. My ODBII scanner spat out the following: "Model X3 28IX_N52_AUT". Does that mean that my engine type is an N52? Is there another way of finding out?

2. Note that I had the awful wheel-grabbing issue before I took the car to the mechanic a couple of weeks ago. Once he unplugged the transfer case, that issue completely went away. No more grabbing at all. Now it's just smaller symptoms like tons of warning lights and no speedometer. So... could it still be a wheel sensor issue even if the unplugged transfer case solved the grabbing issue?

[Captain Hook]

...I took a guess that the engine is an N52 based on the ODBII returns.

Ran the codes through www.bmwfault.codes and got the following for the "48068C, Transfer box: Temporary fault, temperature" code. Along with codes for the transfer box temp, rear wheel speed sensors showed up in the list! The first pic is from the initial report when I ran the code. The lower pic is from when I clicked the "view" link next to the "Rear wheel speed sensor" fault.

[Marty in NY]

Originally Posted by Captain Hook

...I took a guess that the engine is an N52 based on the ODBII returns.

Ran the codes through www.bmwfault.codes and got the following for the "48068C, Transfer box: Temporary fault, temperature" code. Along with codes for the transfer box temp, rear wheel speed sensors showed up in the list! The first pic is from the initial report when I ran the code. The lower pic is from when I clicked the "view" link next to the "Rear wheel speed sensor" fault.

Right, you have the N52 engine on your 28i. The other way to know is to use your VIN on a VIN decode site but I would trust you OBD readers info. The 28i came with the N52 as one of the engines. See the Wiki chart attached. Not sure in your case the engine number will matter but the site wants it.

Not sure I can adequately answer question 2. Cars are complicated these days and they are so networked that one issue leads to several symptoms. When you say the shop unplugged your Xfer case, I assume you mean they disconnected the electrical connector from it, correct? Or did they do something else or in addition?

Have you reset all your codes after the shop disconnected the Xfer case? If so and you are still getting idiot lights for ABS, DSC, etc, that would indicate you have other issues outside of a potential Xfer case issue. As in my case, the two Wheel Speed Sensors that failed caused the ABS, DSC, Airbag and Brake idiot light to come on and stay on as well as displaying the Chassis Stabilization, Restraint System and Parking Brake Reduced messages to be displayed. In addition to those, Cruise Control no longer worked, engine power was reduced and power steering was almost like a manual steering car. Those degraded performance attributes was the cars way to try and protect itself from further damage…smart car!
So you can see how many aspects of the car depends on getting a proper Wheel Speed Sensor signal in order to work correctly. Now, I'm not saying the root cause is one or more of your Wheel Speed Sensors but they are super easy to check, inspect, swap and if you go so far as to replace one or more, they are cheap as compared to a new or rebuilt Xfer case. You just pop one out and pop a new one in, reset your codes and drive a short distance to see if you codes come back.

You will need to determine whether to reconnect your Xfer case or not. If all the shop did was to disconnect the electrical connector, you can just reconnect it yourself from under the car. However, this is how I would probably go about it since its already disconnected.

- Reset all codes
- Drive around the block a few times
- Read and write down new codes

If you get an ABS Wheel Sensor Code, then see which one it is, it should tell you when you look up the code, well mine did anyway
- Swap wheel sensors. Lets say you get a right front sensor code but not a left front sensor code, then sway the two front sensors
- Reset all codes
- Drive around the block a few times
- Read and write down new codes

If the code changed to the left front, then I would say you have a bad sensor that is now in the left front (drivers side)

Then, I would replace that sensor with a new one, I bought mine from AutohausAZ, I bought the ATE brand, they are an OEM supplier. I would then...
- Replace the wheel sensor
- Reset all codes
- Drive around the block a few times
- Read and write down new codes

Keep in mind that since the Xfer case is disconnected, you will get codes relating to it and will just have to ignore them for now until you reconnect it.

If the wheel sensor code does not show up anymore, I would reconnect the Xfer case and make a test drive.

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[Captain Hook]

Semi-success! Before I last wrote, I got a code on my Foxwell that there was a speed sensor problem on the front right wheel. I cleared the codes, swapped sensors between the front wheels, drove it around and retested. The fault code for the wheel speed sensor moved over to the front LEFT wheel. So I'm going to get moving to replace it. Thanks!

Related question: I saw guys on YouTube testing the sensors with a multimeter. I followed their lead with my own multimeter with both sensors once I got them out of the car. But I never got a resistance reading from either sensor on the front, in spite of the OBDII telling me the problem had moved from the right to the left wheel (suggesting that only one of the sensors was bad). Should I replace both of the sensors?

Finally, once I replace the sensor(s) I'm going to try to reconnect the transfer case to see if I get 4wd back, and if the primary symptoms (violent jerking and wheel grabbing on acceleration) go away. Do I have to get it reprogrammed by a mechanic before it'll work?

Can't thank you enough Marty for the lead on the wheel speed sensors. At least one of them is definitely out of commission. I'm hoping it'll solve my main problem. Of course, it could be that the transfer case is also done for, but we'll see...

[Marty in NY]

Originally Posted by Captain Hook

Semi-success! Before I last wrote, I got a code on my Foxwell that there was a speed sensor problem on the front right wheel. I cleared the codes, swapped sensors between the front wheels, drove it around and retested. The fault code for the wheel speed sensor moved over to the front LEFT wheel. So I'm going to get moving to replace it. Thanks!

Related question: I saw guys on YouTube testing the sensors with a multimeter. I followed their lead with my own multimeter with both sensors once I got them out of the car. But I never got a resistance reading from either sensor on the front, in spite of the OBDII telling me the problem had moved from the right to the left wheel (suggesting that only one of the sensors was bad). Should I replace both of the sensors?

Finally, once I replace the sensor(s) I'm going to try to reconnect the transfer case to see if I get 4wd back, and if the primary symptoms (violent jerking and wheel grabbing on acceleration) go away. Do I have to get it reprogrammed by a mechanic before it'll work?

Can't thank you enough Marty for the lead on the wheel speed sensors. At least one of them is definitely out of commission. I'm hoping it'll solve my main problem. Of course, it could be that the transfer case is also done for, but we'll see...

That was probably the same YouTube video I saw, I could not get any readings either. I tried finding out what was inside my wheel sensors but only came up with the fact that there is a bit of electronics in them, not just a coil or resistor and assumed mine were different than the one in the video. I metered both the good and bad sensors and the readings were identical between them. Since I had a hard time swallowing that two of my sensors failed at the same time, I initially only ordered one. Then once that was replaced, I still had a code saying the other was bad so I then ordered the second one.

Like I mentioned earlier, they can fail in different modes so possibly yours failed in a mode that freaked out the Xfer case but if I were you, I would make sure all wheel speed sensors that throw codes have been replaced before reconnecting the Xfer case. It's too expensive to risk damaging it if in case its actually ok.

If all the shop did was to disconnect the Xfer case, I don't know of a reason why simply reconnecting it would not work without any programming.

BTW, I was in Florida when all this happened to me, must be something going on down there

[Captain Hook]

Haha. Oh there's definitely something going on down here, Marty.

By the way, I double checked the deadness of that front wheel sensor by doing a live data test with the Foxwell and driving it around. Three wheels showed consistent speeds. The dead sensor showed 0.00 km/h. So it looks like it's the only one that's given up the ghost.

[Marty in NY]

Originally Posted by Captain Hook

Haha. Oh there's definitely something going on down here, Marty.

By the way, I double checked the deadness of that front wheel sensor by doing a live data test with the Foxwell and driving it around. Three wheels showed consistent speeds. The dead sensor showed 0.00 km/h. So it looks like it's the only one that's given up the ghost.

Fingers crossed that all your issues are the result of that one dead wheel sensor. Keep us posted.

[Captain Hook]

Hey Marty. Super easy to replace the wheel speed sensor like you said.

I'm now trying to find out where the stupid connections are for the transfer case. Remember my mechanic said he "disconnected" it. I know it didn't take him long as he called me only about an hour after he first got the car so I doubt he had to disassemble much to get to the connection(s).

Suppose I could call and ask what he did to disconnect it... but my pride is hard at work especially since he missed the sensor being bad.

There are loads of videos on disconnecting transfer cases for BMW X3's 2010 and prior, but mine is a 2011 and looks very different from those videos. I can't find a single video that shows the electrical connections for a TC after 2010. For my 2011, push the heat shield back and you run right into a mammoth brace. Nor are there immediate connections in the trunk area. Any ideas before I swallow my pride and call the guy?

Thanks in advance.

[ga9213]

45L transfer case has the control unit attached to the case itself, just to the left of the drain/fill plug.

[Captain Hook]

Thanks! And there’s just the one connector right? Pre 2011’s had two connectors, a large and a small.

[Captain Hook]

Gotta say thanks to all. Marty in NY was dead-on about the sensor, and ga913 was a help for reconnecting the TC. We reconnected it, buttoned up the hardware, and cleared the codes. Drove like absolute butter. Shuddering and bucking were completely gone. Took a little bit for the speedometer to fix itself but that's hardly an inconvenience.

Y'all helped save me and my family some $6500. It was a $50 fix in the end. Thanks a million!

[Marty in NY]

Originally Posted by Captain Hook

Gotta say thanks to all. Marty in NY was dead-on about the sensor, and ga913 was a help for reconnecting the TC. We reconnected it, buttoned up the hardware, and cleared the codes. Drove like absolute butter. Shuddering and bucking were completely gone. Took a little bit for the speedometer to fix itself but that's hardly an inconvenience.

Y'all helped save me and my family some $6500. It was a $50 fix in the end. Thanks a million!

Well congrats Captain Hook, sometimes I get lucky and am right I bet you're feeling pretty good right now. I know how I felt after I fixed mine. Happy Motoring!

[383vett]

Nice call Marty.

[KC831]

Apologises for not coming back sooner and providing an update.

Thanks to all for assisting me and a massive thanks ths @Marty In NY.

I followed your advice, purchased a ATE wheel speed sensor, replaced on my driveway within the hour, total cost £66, BMW wanted £4000 to fix!!

All faults and warning lights clears and not more issues.

Thanks again guys

[Marty in NY]

Originally Posted by KC831

Apologises for not coming back sooner and providing an update.

Thanks to all for assisting me and a massive thanks ths @Marty In NY.

I followed your advice, purchased a ATE wheel speed sensor, replaced on my driveway within the hour, total cost £66, BMW wanted £4000 to fix!!

All faults and warning lights clears and not more issues.

Thanks again guys

That's great news KC831! Happy New Year, think of all the champagne you can buy with the money you saved! .. .. or I can send you my HSBC routing number and you can deposit it in my acct

Same experience for me, BMW wanted a fortune but I did it in my brother in laws driveway while there on vacation. I don't mind paying BMW if they're reasonable, especially since I was on vacation, but this is such a simple job. They were going to replace all four, like a cheap shotgun experiment. I thought their techs were highly trained and used only the best diagnostic equipment instead of a shotgun. Well anyway, glad it was nothing more than the sensor.
Oh yeah, happy Brexit too!

[e30lover318i]

Great work on the diag Marty! Another person saved before bmw got they’re claws in!

[Ho55]

I think the transfer box errors are caused by the wheel sensor, beacuse i've just had the same issue. You could expect if the GB controller is not getting correct speed data, it might throw an error.