Things break when leaving Utah

[lkcook]

I purchased a 2016 CrossTrek a few months ago for my daughter. We live in Wyoming, but purchased it in Utah.

After purchasing it, we remained in Utah for a few days and everything was fine; cruise control worked, no warning lights/messages.

Once we headed home and were about 50 miles into Wyoming, the warning messages concerning 'emissions' and 'hill-assist' came on and the cruise control stopped working.

This status remained for a couple of months while at home in Wyoming. Recently, we went back to Utah and around the same area in Wyoming, the error lights/messages went off and the cruise control worked again. The whole time in Utah, everything worked.

Once again, during the return, once we were in Wyoming again (about the same place), the warning messages/cruise control did the same thing and has remained in this state while at home in Wyoming.

Yes, I know - strange indeed. Ideas?

 

[keith3267]

You need to get the codes read and report them here. Most chain autoparts stores will read them for free, but instead of giving you the code, they give you a list of things to replace. Just get the code or codes.

If you are not seeing a check engine light, then the bulb may be burned out. All those warning lights and the cruise not working happens when there is a check engine light.

Just a wild a**ed guess here, but it could be a difference in gasoline.

 

[lkcook]

I have a blueDriver so I scanned it myself. When all of this happens, the 'check engine' light does illuminate.

The check engine related code is P0420 "Catalyst System Efficiency Below Threshold Bank 1"

I'm wondering if it's an elevation thing? We go to Salt Lake City and it's around 4,300 ft, Evanston Wy is 6,750 ft which is where it happens. Our home is around 5,200 ft.

We're going back next week so we'll see.

 

[keith3267]

My best smart alec remark would be to move to St. George. I love that area. But altitude alone should not cause this, something else is marginal. I would look at the O2 sensors, particularly bank one. Usually it is sensor 2 (B1S2) if there is a sensor 2. It depends on whether the back sensor is behind the warm up cat or the main cat. When behind the main cat, there is usually only 1 of them. My second choice would be B1S1 in front of the warm up cat.

OBD2 doesn't detect any issues with those O2 sensors because they are still working, they just aren't responding as fast as they did when new.

But before replacing any of those, look for any exhaust leaks. Any leak, however small fools the O2 sensors and is most often the cause of a P0420.

P0420 means that the rear O2 sensor is following the the front sensor too closely. The front sensor reacts quickly to changes in the A/F ratio and adjusts the fuel injectors. The cat smooths out these sudden changes by storing oxygen during lean conditions and releasing it during rich conditions so all the fuel gets burned. If the rear sensor is changing as fast or almost as fast as the front sensor, then it looks like the cat isn't doing its job. But if the front sensor is switching too slow or the rear sensor is a little erratic, or extra air is getting in through an exhaust leak, it will also look like the cat isn't working.

A good shop will put a dual trace oscilloscope on the outputs of the sensors and can pinpoint the exact cause. Some times the cost of a diagnostics is a lot less expensive than throwing parts at it. Just make sure the shop has an O'scope for this.

 

[lkcook]

Thanks for the info. Funny thing is, my daughter most likely will be going to Utah State next year, so it may be just fine.

 

[keith3267]

My brother went there.