You can take a small file and stick it into the flame viewing hole and clean up the spark wire and the burner tube. As the spark jumps from one to the other, they both have to be clean. Also make sure your spark wire is far enough away to generate a spark large enough to ignite - I had mine too close and it would not light.
Take off the access panel and twist the viewing cover on the cover of the burner tube. You can turn on the frig and then run back outside to see if your getting a spark. It will try a few times before it gives you the fail code.
And double check that your propane tank valve is open. Sometimes air will get in the line so I light the stove to clear the air out. Air will also cause a NO FL code as the frig gives up before the air is cleared out.
Tom and Katharine
'07 Winnebago Tour 40TD, 400hp Cummins
'17 Winnebago View 24V, '02 R-Vision B+
RVing for 20 years & 200,000+ miles