Catalyst monitor will not clear. Need to pass CA emmisions test.

Hello, no - California only allows one incomplete monitor, usually evaporative emissions. Disconnecting the battery is a bad idea - you just reset everything, and yeah - it's difficult to get all the parameters to set. Especially with a Diesel particulate filter and regeneration operation -- it may require more driving to clear that monitor. There's a great article on RepairPal about drive cycles: https://repairpal.com/drive-cycle-issues Other than that, I suggest: half tank of fuel. Cruise control on open road at 57 mph. Cruise like this for about 15-20 minutes. Decelerate, stop. Accelerate again, cruise at 57 mph. Check monitor status. With the DPF, it's hard to know how that one will do, but the rest should clear. Good luck.