We got a 14seer Coleman Echelon in 2007 and it has worked pretty well. All of the sudden if I try to run the AC the outdoor unit turns on for about 1-2 min and shuts off.

I cleaned the outside coils today and noticed a fault light for a low pressure lock out.

What does that mean.
Could I have set something improperly in my tstat?
Heat and Em heat work fine.

Thanks for all help.