So. I have dual Battery National Luna smart solenoid System. I recently removed my ground to chassis as requested by National Luna and Blue Sea Fuse Block Tech. Now everyone 7 days. I have a check engine light show up and I can get rid of it by taking power away from truck for 10 seconds and gone. Any ideas or options on why grounding to the Chassis is done by Factory but not recommended by any aftermarket companies? truck seems to run fine with it without the grounding wire to Chassis. I plan to leave off. Until I know more I guess.