[JWT4700]

Hey all. I need some help with my newly acquired e90. Had the 3 lights come on and had the below codes.
I just put in a new actuator motor (OE from FCP) changed the fluid (along with the diffs and transmission). Used ISTA to reset the new servo actuator and reset for the new oil. I did get a few errors “could not reset with our faults) I tried a few times, finally after deleting the fault codes I got everything to reset successfully! Test drive went ok… for 55 miles. Then they all came on again and it seems like the same codes. It was throwing cows as soon as i started it before, so having it go 55 miles was a little strange before coming back on.
My first question is can I replace the control unit with a used unit and just reset it using ISTA or does it need coded?

I did find water under the seat where the control unit it but I opened it up and it was dry inside.

Secondly I noticed that the car fax service history showed that the previous owner replaced 2 tires at a time for the entire time he owned it (12 years) currently the front tires are at 8/32 and the rears are 4/32. Could a life of mismatched tires taken its toll on the t-case? They are the same brand/model and size. I am getting 4 new continental extreme contact dws06 on Wednesday.

Going back to the water issue, there are two ground plates under the pass floor board, they did not have any signs of corrosion but should I remove them and look closer? Maybe I just have a corrosion ground issue? Kind of at a loss here and any help is appreciated!

[JWT4700]

Dropped the car off to get new tires today. Currently it is back to throwing codes as soon as I start the car. Any ideas where to start? It just puzzles me that the new actuator kept the codes off for 55 miles now it’s back to throwing codes at start up. Hours of searching has yielded the same results, Thise codes are typically due to a bad actuator.

[JWT4700]

Throws codes at start up or atleast before I get out of the driveway. So on Thursday I call the local salvage yard and order up a used t-case module. Friday morning on the way to work it didn’t throw the codes until about 15 miles after I left. Left work Friday afternoon and the codes have yet to return. Put about 200 miles on the car since Friday morning… do I even swap the t-case module or wait to see if the codes come back?

[mikest]

A datapoint for you: I was getting the 5F3A and a 52D1 ("incremental transducer in servomotor, supply”) for awhile in my 2011 335i xDrive. Replaced actuator - same faults. Found same water in passenger footwell but similarly found no evidence of water intrusion into control module. Replaced control module w/ used unit anyway (carrying over values from old unit) and faults went away. No subsequent issues in nearly 2 years.

[JWT4700]

So it’s been over 500 miles with no codes…until yesterday. Now th codes are happening consistently again. I do have a used module…BUT, I just read in another post that if the car is manual (mine is) and the used control unit comes from an auto (It is) then I need to write my VO to the used module. I have no experience with ncs expert. I’m a little hesitant to try it but I may have to learn I guess.