error codes P1150 and P0A93

It sounds like you are having inverter overheating problems. You can't trust a generic codes reader on the Prius.

P1150 relates to the Coolant Heat Storage tank system. Possibly the CHS valve has failed. problem areas:
*CHS tank outlet temperature sensor
*Water valve (coolant flow control valve)
*Cooling system (clogging)
*ECM
This is not a big problem, it just means that the engine will not preheat quickly, but still runs fine. Someone reported that adding a cooling system lubricant (Barr's) has unstuck the valve.

P0A93 relates to the inverter cooling system performance. Either the coolant pump is not working, or there is air in the system, (check the inverter coolant reservoir for turbulence when the car is in Ready) or the electric fans on the radiator are not working (blades were reversed after the repair: check that the fans are blowing the right direction). You will need to look at this soon, as an overheated inverter will leave you stranded and can be $$$ to replace.

 

I think the code relating to A/F sensor is incorrect, a result of a non Prius code reader being used. The light coming on going uphill is consistent with overheating. I suspect Toyota did OK on the pump replacement, but there may be air in the system yet.

And definitely check that the fans are running. Open the hood with the car on, A/C cycling on. The fans are counter rotating, and air should move in through the front of the car. If the repair place reversed the blades, then air will try to flow backwards.

Open the inverter coolant reservoir, and make sure you see ripples moving on the surface.

 

I had a repair shop on my 07 put the fans in reverse. When you stand in front of the car and the fans engage, the air should not blow at you... Unfortunately, this happens...

 

Another give away for reversed fans is that the external air temperature on the mfd goes haywire reading high as as hot air from the rads is blown over the outside air temperature sensor.

John (Britprius)

 

We have a P1150 code that comes and goes on our '06. My local mechanic is stumped as the 1150 dtc comes up as air flow and /or the chs sensor. I would like to resolve the problem but was wondering how long I can let this go untreated; will this cause the car to overheat or can I, as you mention in your post, sort of ignore it? I am also intrigued by the idea of using a lubricant to unstick the valve if it is sticky. Thank you

 

On the Prius, P1150 points to the flow control valve at the coolant heat storage tank. It has nothing to do with the A/F sensor. It is not uncommon for generic code readers to give false readings when used on the Prius, so that may be why your mechanic is confused.

This can be ignored as stated earlier, if you don't mind that the car will take longer to heat up to running temperature.

Make sure that the coolant level in the actual radiator (not just the overflow tank) is full. If your ICE coolant pump is leaking slowly, your coolant level could be low.