I recently purchased a 2016 F-250 XLT 4x4 with the 6.2L gas engine, I purchased it in Montana. While returning from MT to WA state the check engine light cam on. Halfway through the next day it went out. On the way to a ford dealership the next day it came back on. Under diagnostics, P0455 code, (Large evap leak detected, found the purge valve stuck open). They replaced the Evap Purge Valve, and that cured the check engine light indication. The next day, all is well until I pressure washed it at a local self service car wash, (I did not pressure wash under the hood). Upon finishing and starting it, the Check engine light came on again. And is still on.. Current Milage is 141863. I'm taking it back in at 2pm on Monday the 5th of October.

Please advise...
B/R Idaho Manson

 

A question or two.
Did the check engine light come on shortly after each time you purchased fuel? If so. did you put the fuel cap on tight enough?

 

No... The first time I did put full in, I did get a prompt to recheck my fuel cap. I retightened it and that prompt went out..