Prius Gen 2: DTCs P0A92-261 and P0A7A-325 / how to proceed?

Hello, dear P2 experts!

A Prius Gen 2, FL, model year 2008 with 160,000 mi is showing error codes P0A92-261 and P0A7A-325.

I'd like to narrow down whether the problem lies in the inverter or the transaxle unit.

After clearing the DTCs, the Prius can be switched to "Ready" mode normally, the ICE starts and charges the HV battery until it shuts down after a warm-up phase.

Switching to EV mode (available in EU models) works, and driving in EV mode is completely normal.

Without EV mode, the Prius starts electrically as normal. If I give it more gas, the ICE kicks in and accelerates normally with increasing ICE rpm and electric assist. After about 10-20 yards of driving, there is a noticeable jerk, and the warning lights for the red triangle, VSC, and yellow engine symbol come on. The ICE continues to run at a slightly increased speed, but pressing the accelerator pedal has no effect.

After stopping and clearing the DTCs, the exact same behavior can be reproduced.

With the DTCs cleared and then letting the car run in Ready mode for 15 minutes (heating request at max. temp), the DTC P0A92-261 appeared again without driving. Clearing the error didn't help anymore, the error came back immediately. After the driving tests and the idle run, the transaxle unit and the electric motors were certainly at a higher temperature. So there could also be a temperature dependency involved.

Does anyone have experience with these DTCs?

What do you think?

I find it interesting that everything seems to work for a certain amount of time (warm-up phase, EV mode, charging HV battery, accelerating with ICE and electric motor), but then this "jerk" occurs. What exactly could be the cause of that? How would you proceed in further analysis?

If possible I would like to identify the defect component (e.g. transaxle or inverter) before I decide on replacing any of them.

Thanks, Thorsten

 

Thanks! Yes, I use Techstream for all the readings and have the Toyota manuals. Maybe I'll do some of the resistance measurings of MG1.

 

Yes, that's what I expect, but hoped to shorten a bit!

 

Interesting findings!

As I wrote above:
"I find it interesting that everything seems to work for a certain amount of time (warm-up phase, EV mode, charging HV battery, accelerating with ICE and electric motor), but then this "jerk" occurs. What exactly could be the cause of that? How would you proceed in further analysis?"

Could the trans (or one of the MGs) be broken if it works fine for a short while running in EV mode and together with ICE until the "jerk" comes?

 

The transmission fluid has never been changed at this car. It was always in service at the Toyota dealer. In Germany the service instructions don't ask for a change. They call it a 'lifetime filling' - which I don't believe and change it regularly at my Prius!