[DRMCEO]

Got an error code for the crankshaft position sensor so I replaced it with a bremi brand unit. The car now never starts first try, but will start second try and goes into limp mode with 2 dsc errors in the idrive. The tach intermitently works but when connected to a scanner it shows the engine rpms on the scanner. If I delete the error codes with ista it cuts the car off and the errors return on restart, but if i delete the codes w the autel scanner while running it will delete the codes and they wont return and it is no longer in limp mode and the tach seems fine. off course once i turn it off and restart errors return. One thing I notice about the tach is its not exact. when the car revs at 742 rpm the tach is solid at 750 even as the revs fluctuate around the 740-760 range. The crankshaft signal must be going through to the dme because the scanner reads the rpms with no issues before and after clearing the codes. I'm wondering if this is an issue with the DME??? I am not sure what to do at this point and trying to avoid taking it to a shop. Any suggestions would be appreciated. I am new to this car and f10 platform.