Help! Gen 2 With P0A93 and C1241 but Inverter Coolant Pump Appears to be Functioning

Hi PC community - long time lurker, first time poster here. Thanks in advance for your help!


Yesterday, I was driving home on the freeway going about 70 mph when my 2009 Prius gave me the red triangle, the vsc, the (!), and the check engine lights. I pulled over and connected my cheap OBD scanner, and it gave me P0A93. I noticed no difference in performance or feel when the codes came on. This struck me as strange since I had replaced the inverter coolant pump exactly 11 months ago. So I went to O’Reilleys to have them verify the code. Their scanner gave me P0A93 and C1241.


Currently I have 239k miles on my Gen 2. I replaced the inverter coolant pump 11 months ago at 226k. Unfortunately I replaced it with the Dorman aftermarket part (I know, bad call! It was a Sunday, and I couldn’t get the OEM part anywhere in time to have the car ready to go to work Monday). I have not had any issues following the repair up until yesterday. The previous time that I received the P0A93 code, I noticed that the AC stopped working and was blowing hot air. I also had an issue where the brakes went soft momentarily before returning to somewhat normal performance.


As I started to dig into troubleshooting my current P0A93 code, I realized that I did not flush or bleed the coolant when I changed the inverter pump 11 months ago. I simply switched the parts and topped off the small amount of coolant lost. Could air in the system be causing my current code despite having no issues for 11 months? The Dorman pump does seem to still be functioning properly as I have turbulence in the inverter coolant reservoir and I can hear the pump whirring when I put the car in ignition ON.


I’ve also now read that I could also be getting my P0A93 due to an issue with the cooling fan. I’m not quite sure how to diagnose that. At this point, I think my next steps of action are:

1. Check 12V battery and connections since it gave me the C1241 code.
2. Bleed Inverter Coolant System to rid it of any air.

Do yall have any other recommendations or experience that could help me get this problem resolved?


Thank you very much!!

 

Thank you! I was unaware that the failure was gradual. In that case, it will be easy to swap out the Dorman for an OEM part. Is there a way to confirm that the Dorman is gradually failing without Techstream??

 

Thanks PriusCamper. It wasn’t a particularly hot day. Today, I bled the system and checked the 12v and connections. Everything seemed fine there. I’ll check for obstructions near the radiator, then probably clear the code and give it some drive time to see if that did the trick

 

Thank you for this info. I was unaware of Dorman’s reputation prior to doing this repair; however, it was a Sunday afternoon and I had no other option if I wanted the car to get me to work Monday morning.

I am leaning towards going the route you recommended. I should I have looked at the pump when the code came up before turning the car off. As you eluded to, once I turned the car on again to look at the pump, everything seemed to be working fine.

I erased the code, bled the lines, checked the 12V, and have driven about 50 miles (20 miles was the longest so far at one time). Up to this point, the code has not returned. I think I will swap the pump for an OEM - if nothing else than for the peace of mind.