I get a check engine light (emissions) that shows up every time I tow my 22' Airstream Bambi. It's well within towing spec - and the check engine light disappears after I've disconnected and drive without the trailer. Happens every time I tow ... has anyone else seen this?

 

I have been towing for 10K miles or so on my 2022 P300 110 and have had no such issue. Assuming your gas cap is tight in either case, and just guessing, it sounds like either a wiring problem in the vehicle, Including in a control module, or a sensor issue in the emissions. Or maybe it has the PCV valve leak ?

It has thrown an error code, so your dealer has something to go on. They should be able to trace it, hopefully.

Good luck !!

 

This happened to me while pulling a camper as well. After multiple disconnections and connections while the car was off or on, the only thing I could guess at was either the light connector or the Anderson plug for charging the camper battery that goes to a DC-DC charger. Doing more tests during the week and will let you know.

 

Good luck and please do share any breakthroughs. My assumption right now is that it's some sort of faulty sensor in the emissions system - or there is a program setting that needs to change (and isn't) for when in tow mode.

 

My Apologies for the delay. In my case after running some test, the issue was wiring in the camper harness. I replaced and rewired and after a week no check engine light has come on. Probably the first place to start as it is a cheap fix.