My wife has a 2018 Cooper S with the 2.0 liter Twin Turbo I-4 and an automatic trans. with about 104k on the odometer. Last fall a "drivetrain error" message appeared but the check engine light didn't go on and the car ran and drove fine. A couple months ago the check engine light came on with the P13C9, P054B and P0015 codes, and the car idled very rough and lacked power because the timing was off. Took it to my very trusted mechanic (who has worked on my own 1995 BMW E36 for a decade) and he replaced the VANOS solenoid and one other part that I can't recall the name of. He reset the engine computer, cleared the codes, and the car ran and drove great. However, on my way back home (20 minutes into my drive home) the check engine light came back on and the SAME three codes re-appeared. Since then it has been idling and driving fine, but the car has to pass Oregon's strict DEQ testing next month and my mechanic is telling me that he can replace the two parts under warranty, but he added that he thinks that engine needs a full overhaul. My wife and I need to get this car to pass DEQ somehow so we can drive it legally for another 4 to 6 months while we pay off the loan on it. Then we will sell it and get rid of it. To accomplish that I am even considering borrowing a professional OBDII code reader that will allow me to clear the codes immediately before taking the car into DEQ. Is there anyone out there reading this who is skilled enough to speculate if the engine is indeed bad? Compared to my BMW E36, this car is a poorly designed and poorly engineered piece of crap. (NO OIL DIPSTICK!! )

 

I doubt the "engine is bad" (that's a pretty high bar) but certainly something is going on in there.

Those P-codes are generic OBD-II codes. What you need out of the gate is a scanner capable of reading BMW/MINI-proprietary codes. You will definitely have at least one such code, and probably more than one. Point is that those proprietary codes are more granular - you may still have diagnostic/figure-out to do, but they will get you a lot closer.

The cheapest way into getting those proprietary codes is the combination of the BimmerLink app (will load on iOS or Android; you'll find it in whichever platform's app store) and a compatible OBD-II adapter (a common one is the Veepeak OBDCheck BLE Bluetooth). A full list of compatible adapters can be found at this link: https://bimmercode.app/adapters/ (note that both BimmerCode and BimmerLink are made by the same firm and a given adapter will be compatible with both -- but it's absolutely the BimmerLink app you need, so don't get mixed up).

Separately, regarding clearing codes: after you clear codes there is a stack of tests that have to run and complete before OBD-II "readiness" is present. If Oregon DEQ is like most of its sister agencies in other states, flunking that readiness check will flunk your emissions test. In the first drive after clearing codes only some of the readiness tests will complete, and getting the rest of the bare minimums to complete is not the on-demand/at-will easy task one might think. BimmerLink will allow you to clear codes as well as any professional OBDII code reader, but that doesn't get around the readiness issue you create when clearing codes.

With the code-clearing readiness concern in mind, your best bet is to get those BMW/MINI-proprietary trouble codes out of the car, and continue more informed diag from there.