2011 Pana4 "PSM failure"

[atilla91]

2011 Pana4 64K.  I bought 2 years ago, still under CPO.   Everything works as far as I can tell, incl PSM.
Starting a few months ago, every couple weeks, “PSM failure” pops up while driving normally (see pix).  
Then PSM, Autostop/start, and Sport mode are all disabled.    Re-start the car, all working again.
After clearing all faults, Duramatic shows PDK (U0418) and HVAC (3277300/3201f4) faults, seem always on.
Then no more faults until the "PSM failure", when Duramatic shows 5 faults all at once:  
        >engine (B0300) - trans mount valve -1-/-2- -N262-/-N263- short circ to B+
        >PSM (17216/4340) - brake light switch implausible
        >PSM (12656801/c120a1)  - Center diff lock control unit fault memory content
        >PSM (8325/2085)-  Sport mode center diff lock, faulty
        >PSM (8330/208a) - Sport mode, faulty.
I clear all 5 and they do not come back until another "PSM failure".
I need to see dealer for PDK oil change shortly, so looking for any advice on a fix prior to seeing.

Maybe unrelated observations:
1)PSM failure seems to happen more when I have a passenger.   Always on freeway.
2)sometimes 3 days, sometimes 3 weeks.  Maybe more often 10mins into trip, but some earlier and one at an hour.
3)sometimes in Duramatic I see about 90 faults on Seat Electronics Passenger for "implausible signal"
4)occasionally see CAN Gateway and Electronic parking brake fault with same (3277300/3201f4) as HVAC always has.
5)I changed oil, flushed PS fluid, brake fluid in December.  Changed rear pads/sensors last month.  All dealer parts/fluids.

[JFP in PA]

Welcome to RennTech :welcome:

 

As there seems to be a lot of communications issues going on here, I would suggest taking it to the dealer while the CPO is still in effect.

[atilla91]

As follow up, Dealer reported that they replaced the Brake Light Switch.   All faults above were cleared (except the seemingly always on HVAC one).    It has not run long enough to be sure the "PSM failure" is gone.    Brake Light switch was one of the indicated faults,  but it does seem like a lot of other faults for just that.   I guess I have to wait and see what happens next.