i have an 02 summit 700 recently had the oil tank off ( to repare ). on the bottom of the tank there is a float from were the line gose to the pump if it is the same tank or set up your float might be stuck just thot i would tell you i may be wrong.
It could be a problem with the RER system. I think the oil light comes on when the engine is running backwards. That would be a sensor or wiring problem.