What is the temperature limit of the motor generator 1 and motor generator 2, before a code comes from these overheating? 2 days ago on a long hill trip, going up and down, my 2012 Prius C motor generator 2 temperature got to 116° C, seems hot but i would like to know what is the maximum temperature these can take.
I understand the ATF to be the most temperature-limited thing in there, and that should be good up to about 125°C
In the Repair Manual series (more info), the malfunction thresholds for the “Drive Motor ‘A’ Temperature Sensor” (P0A2B, P0A2C, P0A2D, and P0A2E) and “Generator Temperature Sensor” (P0A37, P0A38, P0A39, and P0A3A) diagnostic trouble codes are either not mentioned at all or stated only as “TMC’s intellectual property,” that is, trade secrets of Toyota Motor Corporation. The Data List pages give the following “Normal Conditions”: Motor Temp No2 (MG1 temperature): While driving at an ambient temperature of 25 °C (77 °F): 25 to 100 °C (77 to 212 °F)Motor Temp No1 (MG2 temperature): While driving at an ambient temperature of 25 °C (77 °F): 25 to 90 °C (77 to 194 °F) I don’t know if temperatures above these limits are necessarily abnormal, however.
If the ATF gets past 125° C what could happen to it? My Prius C has 126,000 miles, still the original ATF.
Well, i guess the flat wire stators can take higher temperatures, maybe that's why Toyota removed the coolant cooler from the transaxle.
That's roughly the point where some permanent chemical changes will start to occur in many oils. The oil breaks down a little bit, can form some waste deposits aka sludge and lose some useful lubrication properties. A few hours per year at 116 isn't going to hurt anything. My own theory is that with the lighter weight of the Aqua model, they were able to simultaneously eliminate leak potential, reduce the amount of coolant required and trim the parts count a little. All good for cost savings and even further weight savings. Similar to the use of a single radiator fan where all the big Priuseses have two.
Well good thing that it was at those temperatures for a few minutes, when i arrived i turned the car off for a few hours. I see, makes sense, the Prius C being made to be cheaper to buy, but it has also proven to be more reliable, i have yet to see a failed transaxle in a Prius C.
I've gotten MG1 and MG2 to higher temperatures and at some point the car goes into a 80% power mode to protect the system.
I don't remember but maybe some searching might show. I want to say that it was a temp warning with the red triangle.
My experience with a v is mg temps are close to engine temps. 240f would be way too high in my case even though the stated limit is at 323f. In the v design there is an extra coolant loop from the inverter pump to the transaxle because of the v's higher load carrying capability. As a result transaxle temp can impact inverter temps which are alarmed at 149f. That loop goes to the inverter first, the transaxle and back to the radiator.
Toyota should have added a separate small cooling system for the transaxle, the inverter is quite sensitive to temperature and using the same coolant from the inverter to cool the transaxle does not seems like a good idea for the lifespan of the inverter.
Actually the v’s transaxle coolant source could be the engine water pump. (Edit: It is the inverter water pump. See below) Recent 102f Ambient after Freeway Drive
Nope, the engine has one cooling system, and the inverter and transaxle have the other one. v is a little bit different in having a second water jacket on the MG2 side. (Those passages are also present on the non-v Gen 3 liftback transaxles—it's the same aluminum case—but without the cover plate and hose nipples to close them off and make a usable water jacket.)
