01 Check Engine Light/Warm up valve

[lrwilley]

I sometimes use the warm up valve as an engine brake when towing. Every time I do, the yellow check engine light comes on. Will reset after two cold starts. Anything I can do to stop the light from coming on? I have talked to others who do the same thing. I am the only one who gets the light.2001 F350, 2wd, auto. Thanks.