Crank Position Sensor Failure
 

Can anyone here describe symptoms of a intermittently failing crank position sensor? I think that's what I've got going on. No codes, but the car will cut out momentarily above 3500 rpm. It doesn't do it all the time. I hate intermittent failures, they're so frustrating to diagnose. I wish it would just fail completely, then I could replace the offending part.

Does it not use crank and cam position sensors to calculate what it needs to so not sure if you would feel anything cutting out. Have you done any other checks? Coilpack for corrosion possibly?

:)

It's not the coil pack or the wires; those were replaced recently.

Usually if a cam sensor is acting up you will get a fault code p0341. Then the triangle light will come on. Then the crankshaft sensor will take up the slake of the cam sensor fault.

Not an R53, but have been dealing with this intermittent issue on an E46 (BMW 325i). No codes, stutter at speed and super random and VERY annoying. Wife refused to drive the car fearing it would die at any moment. Some days no issues at all and then later on, the behavior comes back right away. After fuel pump, filter, cam sensors, plugs, coils, checking grounds, I finally bit the bullet and replaced the crankshaft sensor. So far, after 250 miles, the random intermittent has not returned. Mileage is at 195K miles.

For another car, the crankshaft sensor just flat out failed and check engine light came on. Hard to start, limp mode, CEL, the classic failure. Codes confirmed the sensor went kaput. Replaced it and all was fine afterwards. Mileage was about 200K miles.

Maybe ~200K miles is around the limit for a crankshaft sensor???

Thanks for your input. You're confirming what I suspect. My Mini has exhibited all the same symptoms you've described — including the wife won't ride in it! I too, have replaced all the items you mentioned & more; all to no avail. The thing that makes me think it a CPS is sometimes when I'm driving & it cuts out, the tach drops immediately, only to come right back up as soon as the stammering stops. If the CPS was momentarily cutting out, the ECU would think the engine is spinning 0 RPMs; & the tach would reflect such, as it does.

I wish the damnable thing would just fail completely, then I would know for sure what it is. I HATE intermittent failure! It's so hard to diagnose.

Sounds like you've tackled the problem. Do us a favor & report back after a few thousand miles; that will be the real litmus test.

BTW, my Mini has just a tick over 200k.

Yep, will do. I am eager to get this intermittent issue in the rear view mirror as it really dampens the trust factor.

Ironically, the R53 has 246K and it presumably has the original crank sensor since it's not been swapped out yet by me or the kid. Did I just jinx that car?!

Probably. :lol: