PRIUS 2005 INVERTER ASSEMBLY OVERHEATS

The inverter is probably the most expensive part in the entire car. I would tell him to stop driving it and take it to repair shop or even the dealer to get the inverter coolant pump fixed. The pump can still be functional and yet throw codes. Think of it as a dying breath.

 

You are not correct. There are two cooling circuits on the Prius–an engine cooling circuit and an inverter cooling circuit–and you are confusing the two.

The P1121 is Coolant Flow Control Valve Position Sensor Circuit Stuck and is related to the engine cooling circuit. Usually the valve is replaced to fix this problem.

Given what you've said, I'm surprised there are no codes relating to the inverter overheating. Even so, check the inverter reservoir for fluid movement/turbulence when the car is in either IG-ON or READY. If you don't see turbulence, indicating the fluid is circulating, replace the inverter coolant pump.

Definitely drain the water in both coolant loops and refill both with Toyota SLLC, (or you might consider getting Toyota LLC concentrate and mixing a stronger mix (using demineralised water) to take into account the water left in the circuit. No modern engine should be running long term on just water, you have no idea the level of internal damage the will cause.

The only other code of significance is C1241 = Low Battery Positive Voltage, so check the 12 V is good–charge up and then test under load to see if will hold a good voltage (>11 V) for 10-15 min. But, I'd say replace and be done with it. Save your data before you start and then clear all codes. See what codes come back, as poor 12 V battery health is notorious for setting bogus codes.

 

Ditto the above.

An easy way to check inverter pump operation is to put the car into "IG-ON" mode, engine off, and inspect the coolant, or excuse me--water!?--in the reservoir at the inverter. Remove the lid and shine a light onto the liquid and you should see some turbulence. With your head right there, you should also hear the quiet hum of the pump operating, behind the left headlight.

If the hum sounds good but the flow isn't visible in the reservoir, there could be air in the system. This is very easy to bleed with two small wrenches and a short piece of tubing. Get instructions from YouTube.

Not only is water causing a LOT of corrosion problems in very expensive and critical parts, it is not as effective at transferring heat as the proper mix of coolant is.

 

Did you even read my post?

P1121 is NOT an inverter code. It is a control valve in the engine coolant loop. Go back and read my post #3 and Andrew's post #4. If you don't understand something we've said, please ask. But no one can help you if you don't take on board the advice given.

 

NO.

I think there is more than one problem.

You more than likely have a failed Coolant Flow Control Valve. You have a code that indicates this - P1121. Get a new valve and replace it. That is that problem fixed. BUT, it has nothing to do with any problems you have with any inverter issues.

When you replace the Coolant Flow Control Valve, take the opportunity to drain the water from the radiator, heater core and CHS tank (that is, the entire ICE coolant loop), and refill with Toyota SLLC (super long life coolant) or equivalent.

You possibly have a problem in the inverter area to do with over heating. But there are no codes to indicate this, only what you have said indicates this. One thing you need to do, in any case, is drain the water and refill with Toyota SLLC (or equivalent). Having water in inverter coolant loop (or ICE (internal combustion engine) coolant loop, for that matter) will not help things if you are having overheating issues. BEFORE you do this, check the Inverter reservoir (not the ICE radiator) for fluid turbulence when the car is in READY* (or IG-ON*). You have been asked to do this at least three time in previous posts. Can you please do this and report back the results. This will tell us whether the inverter pump is working or not. Thank you. If it does turn out the inverter coolant pump has failed, you will need to drain the fluid anyway, so you may as well take the opportunity to drain and refill the coolant with SLLC while replacing the pump.

You will appreciate that is difficult to diagnose cars remotely, but is even harder when advice is given and not followed. We would like to help, but communicating poorly (or not at all) makes that very difficult. I hope you can see things from this point of view.

Please post your results from this test and keep us updated with your progress.

Hope that helps to clarify.

Location of the Inverter Reservoir:

* the silver unit to the right of the reservoir is the inverter.

Location of the Coolant Flow Control Valve:


* Car mode cycles:
ACC mode ...... With the car in OFF, and the foot OFF the brake, press the start button once.
IG-ON mode ... If the car is in ACC mode, with the foot still OFF the brake, press the start button once more.
........................ If the car is in OFF, with the foot OFF the brake, press the start button twice.
READY ........... With foot ON the brake, press the START button once; this can be done when the car is in any other mode.
OFF ................ If the car is in READY, press the START button once; it does not matter whether the foot is on or off the brake.
........................ If the car is in ACC mode, with the foot OFF the brake, press the start button twice.
........................ If the car is in IG-ON mode, with the foot OFF the brake, press the start button once.

 

BTW, From where was this car imported, or was it supplied by Toyota in your country?

I ask this, as it may not have the coolant heat store tank (as pictured in my previous post). If it was imported from any destination market other the USA, it will NOT have it.

 

Sounds like you are getting to the root of the problems, and thanks for the feedback. Good luck with the repairs.

Let us know how you get on.

 

Answered in you other thread. It is not a good idea to cross post, particularly if it has no relevance to the thread. Taking a thread off topic only makes it confusing for everyone.