How do I know if I need a coolant pump?

head gasket? are you losing coolant? sorry, you're talking about inverter coolant.
how many miles on her?

 

if there's no turbulence, the pump is kaput.

it seems to me that the misfire code is related to the white smoke. but if it's not coolant, oil in the cylinder?

 

i'm not positive, but i don't think so. see if there's a you tube.

 

P0A93? It will help if you can provide the codes the car is storing. It's somewhat confusing as of now since an inverter pump failure and a cylinder 3 misfire would be completely unrelated. An engine coolant temp code, possibly indicating engine water pump failure could be related to the misfire and to the lack of heat/white smoke out the tailpipe. These factors would indeed point toward a head gasket issue. It does appear you understand turbulence in the storage bottle is with regard to the inverter loop. If you're looking for turbulence in the engine bottle, there shouldn't, and wouldn't be any. Apologies if you understand all of this but as I read the thread thus far it's not clear to me.

 

My guess would be new coolant pump and new ignitor (coil) for cylinder 3. The coil is part of the spark plug connection. If the coil is intermittent you should be able to feel it when accelerating. If it's completely gone not so much, but it would probably cause the "smoke" from the tailpipe (unburned hydrocarbons loading up the cat) and if not attended to soon it could overheat the cat.

Be happy paying for the pump. It's a part you want to be reliable. 200k mi. is pretty good reliability. My gen 2 engine coolant pump failed at 40k km! It was mechanical (belt driven). The inverter one was electric.

There are two on the car. I'm not sure reading the posts which one we're talking about. Inverter one is even more important than the engine one for us northerners (engine runs cold anyway ). Just joking, they are both important. No heat would be the engine pump. No coolant flowing in the inverter fill tank is the inverter one.