I suspect that P0170 is generic to a number of faults.
One of the first things was to check freeze frame. shows p0170 as long term fuel trim.(15.6 fixed) shows nothing else of much use. light load,, low rpm speed around 45kph and air and water temp norm. Nothing pending.
For some reason solus only gives fuel trims on GM in EOBD.
Tested fuel pressure KOEO 55 psi KOEO 52-54 psi
Also the car is auto, just makes gunning it that more awkward.
Might just try it on Delphi, sometimes that shows data not covered by solus.
The only suspect thing is, the external air temp sensor was reading -40c. last reading was -6c. had this of been IAT it would make sense but I can find no correlation to ECU on autodata wiring diagram. So I think it serves dash readout only which read +12c which was correct?
On early BMW it served dash read out and ecu

Regards

p.s have to wait for MIL to reset. Would help if I could repeat it on regular basis.
I suspect that the LT trim @ 15.6 is border line pid set