2000 Caravan Sport 3.3L

Get a compression test done to eliminate a warped head or cracked head . Hopefully you have not cracked the block as this costs 6000 dollars AUD to fix or $3500 AUD for a Reco Engine.
If it is an alloy head the two metals cool at different rates and warping or cracking can occur. $$$$$$$ costly $$$$$$ to fix

So being it doesn't clatter in electric mode, a safe assumption is the noise is with the gas motor.

Usually a clattering noise is valvetrain noise, like a lifter not pumping up.

Low oil will cause this.

3 quarts low would probably definitely cause this!

You need to find out why you lost 3 quarts in only 80 miles!

A clattering sound could be a knock sensor. They are made to tell you there is a problem with the engine or it could just need to be replaced. If you dont have any fault codes or loss of power you might just need a new one but start at the simple spots first. Check the serpentine belt and make sure its on tight check your intake manifold and exhaust manifold for leaks and make sure the sound your hearing is not a bad lifter or rod. You can remove the valve cover and visually inspect most small cars. Check all of your fluid levels because if your low on oil it will cause this aswell

You will need to remove the valve cover and inspect it, otherwise it is anyone's guess what the noise is.

The engine needs to be replaced. Clatter can be the main and rod bearings or the lifters. Lifters clatter with no oil pressure. Low or no oil pressure is usually bearings. Oil pumps rarely go bad, they are a very simple set up And work forever. I have never replaced a pump because it was bad. And running an engine for 30 seconds would not do that kind of damage. But running a long time low on oil will.

is this even in summer time, or has this just started occuring since winter got here... if its since winter got here, its perfectly normal to hear the valves clatter when the engine is cold.... if it knocks in summer time also, you have something a little more serious goin on, could be rods, could be the mains, could be both rod and main bearings, lifters, scarred cam... but being this new of a vehicle, id say its just a clatter from the lifters being in cold weather.. hope this eases your mind a little

more than likley it will be that it is low on oil or coolant, but it could be that you need a new thermostat

The camshaft sensor wouldn't explain the clattering noise. But a timing chain would explain both. Clattering from a loose chain and the camshaft sensor code from when the chain broke and the camshafts stopped turning.

if the oil pressure is actually low (and not just a false indication) then you should hear valve lifters making a clatter .. if they are not making noise then you might just have a bad oil pressure sending unit (small part that screws in) .. if you do hear clatter then in some cars the intake screen on the oil pump can be clogged with sludge ... that doesnt happen often with the caravan but possible if oil hasnt been changed for a long time ... the oil pump is located inside the crank case and service requires removal of the pan ... if you have valve clatter then driving the car can do a lot of damage if the problem is not fixed ... check the oil filter for damage or clogging ... of course check oil level. a milky appearence in the oil would indicate water in the oil (often a blown head gasket) ..

Either your battery is on the low side, or you have a dirty connection to your battery. Give the battery terminals a little twist and see if it helps any.