Anyone Know What This Maintenance Reminder Is For?

[ZetaTre]

Originally Posted by bawareca

Ok,let's start from the beginning.I actually like your write-up for the diesel CCV oil separator and i planned to make something similar.It actually becomes necessity with the tune I am developing with some overseas partners.


The same way I am mistaken,you may be too.So the correct term would be "statements that I believe are inaccurate"


I am quite mistaken in that case and I have no idea how that idea got into my head I believe the oil quality in the VTG is monitored by the VTG control unit by terms of clutch pack slipping,but do not quote me on that.


There are some clues in this post that it is kind of irony.Regardless of the intended fluid life,you will not get this message on the dash,even for the engine oil change.


First of all,there is a huge misunderstanding how the tampering dot works on the older models.The mileage from the cluster is stored in the light module and the EWS.If you set the mileage to 0 in the LM or EWS it will take the value from the cluster first time the car accelerates to ~30 mph.If you lower the value in the cluster and the values in the LM and EWS are higher the tampering dot will illuminate.Same will happen if you change any of those modules and the VIN numbers dont match,regardless that the mileage may be accurate.
In the newer generation BMWs the mileage is stored in the cluster and CAS actively,+many other modules but only passive.If you lower the mileage in the cluster and install it on the car it will take the mileage from CAS,no tampering dot will appear.Vice versa is valid too.If you install a different cluster ,or different CAS and VINs do not match,the tampering dot may appear.But many other functions will not work and the car will be a mess.I have never seen the dot illuminate on any of the new models,and after deep google research this is the only thread I found that mentions the tampering dot:
http://www.xoutpost.com/bmw-sav-foru...-dot-came.html
But it is not very definitive after all.So yeah,the truth is out there
Sorry for the long post,at least we keep the forum alive and kicking.

Originally Posted by JCL

Perhaps this will help.

So we are agreed that the alert is for the transfer case. Yes, it is condition based monitoring, but not via a sensor in the oil. That is the engine oil condition sensor, and it measures capacitance, not resistance. It isn't picking up metal particles in the fluid, but rather the depletion of the additive package.

The transfer case fluid condition is not based just on mileage, like the oil change interval was based on fuel consumed. It is based on changing frictional characteristics of the gear oil, and the control box recognizing that those characteristics are crossing a threshold, measured by comparing slip characteristics (input and output speeds) and clutch engagement pressures (actuator torque).

I don't have a quote from the manuals on this iPad, but here is a quote from a BMW tech with an extract from the manual which covers it. Sorry I had to use a forum post but it does include the extract from the technical literature.

http://www.xoutpost.com/881911-post7.html

Edit: there are likely differences between the various x-drive transfer cases as to the above details. I know the procedure changed relating to resetting the TC adaptations at some point.