Hybrid Auris P0A7A inverter fault code - inverter is new

[KGYM]

Hi folks,

was wondering, whether any of you have seen a similar issue.

Our 2011 Hybrid Auris (bought in 2022, 65k km (!), kept as second car, very underused) gave us a P0A7A fault code late 2022. No other codes are showing. This is supposed to be a problem with the inverter, performance was held back, but the hybrid Battery still worked. Brought it to an official repair shop, they wanted to replace inverter for $2500, but would've given no assurance that this would work. Funny thing: inverter was replaced in late 2021, so nominally it can't be at fault.

They weren't really sympathetic at the shop, so we took it to another one, based on a recommendation. The repair guy there took out and checked the inverter, it works like a charm (it is less than 2 years old and ran for ~10k), so as a last ditch effort he changed the gear oil - which was much needed, it looked like purple cream instead of rose colored viscous oil. He told us to get back to him if the fault code reappears, and he will get a hold of some extra help.

Our repair guy has some ideas on how to proceed, but in general the situation is unnerving for us. I don't necessarily have a problem with expensive repairs, but the mystery fault code is a big issue. I've been reading up on this, and several people have written about possible transaxle or HV ECU failure.

[Saxmaniac]

Sounds like people are just guessing at the problem instead of diagnosing properly. Did mechanic put the proper gear oil in the transmission as it needs to be the right stuff as electrical windings of motors may suffer damage if not? If mechanics are just guessing you'll waste a lot of money, there are at least diagnosis flow charts in the Toyota service data, you could take out a short subscription and download any relevant pages 

 

[TonyHSD]

You are right.
Very likely not an inverter itself fault., perhaps ecu or the high voltage cables connection. I haven’t experienced anything like that yet but quickly looked online suggests inverter , ecu or the cables connectors. Visual inspection is needed and thoroughly check the cables and connectors for corrosion or damage, like been eaten by rodents. Inverters on these cars aren’t repairable much if anything can be repaired at all. The transmission fluid can lasts ages although better be changed than not. Inverter water pump is what usually fails and then the consequences.
In your particular case as old car not been in use much likely a corrosion or rodents attack and damage to the cables. These two you need to look at and the ecu. 
Good luck 👍

[flash22]

The gearbox needs the correct oil, It's not a normal gearbox

what is the HV coolant level like ?

Any other codes ?

Has the 12v Battery been replaced ?

 

[Parts-King]

11 minutes ago, TonyHSD said:

You are right.
Very likely not an inverter itself fault., perhaps ecu or the high voltage cables connection. I haven’t experienced anything like that yet but quickly looked online suggests inverter , ecu or the cables connectors. Visual inspection is needed and thoroughly check the cables and connectors for corrosion or damage, like been eaten by rodents. Inverters on these cars aren’t repairable much if anything can be repaired at all. The transmission fluid can lasts ages although better be changed than not. Inverter water pump is what usually fails and then the consequences.
In your particular case as old car not been in use much likely a corrosion or rodents attack and damage to the cables. These two you need to look at and the ecu. 
Good luck 👍

We have seen many a rodent attack on cables in the past

[flash22]

ATF-WS does turn brown/dark purple with age (bright red when new) - find out what was put in it

 

[KGYM]

Thank you all for the replies, it is actually very calming to see several people thinking in similar directions. I am taking the car to the Toyota repair shop on Thursday. The mechanic told me something about him getting a hold of some expensive and exclusive tool to go futher, he probably referred to a diagnostic or programming tool for the ECU. We've had to replace the 12V a few weeks ago, but the problem came before that and reappeared after. I can't speak for the other stuff.

As for the oil, I am sure it is the right one, this is an official shop, and this specific mechanic has ~20 YOE.

[flash22]

That would be techstream - its very expensive if you get a top of range kit but on the other hand you can get a cheap Chinese clone interface with software for <30 euros

 

techstream is a powerful tool if you know how to use it, and will be able to properly diagnose the hybrid system

[Devon Aygo]

As cars have become more technical/electronic the traditional DTC code of 5 digits e.g. P0A7A was expanded to add 3 more digits in the case of P0A7A you will need the extra 3 digits to carry out diagnostics:

P0A7A-122	Generator Inverter Performance	- Power management control ECU - Inverter with converter assembly - Hybrid vehicle generator assembly - Hybrid vehicle motor assembly - Generator cable - Motor cable - Wire harness or connector - PCU fuse	Comes on	Comes on	Click here
P0A7A-130	Generator Inverter Performance	- Power management control ECU - Inverter with converter assembly - Hybrid vehicle generator assembly - Hybrid vehicle motor assembly - Generator cable - Motor cable - Wire harness or connector - PCU fuse	Comes on	Comes on	Click here
P0A7A-203	Generator Inverter Performance	- Inverter with converter assembly - Hybrid vehicle generator assembly - Generator cable	Comes on	Comes on	Click here
P0A7A-322	Generator Inverter Performance	- Inverter cooling system - Cooling fan system - Power management control ECU - Inverter with converter assembly - Hybrid vehicle generator assembly - Hybrid vehicle motor assembly - Generator cable - Motor cable - Inverter water pump assembly - Wire harness or connector - PCU fuse	Comes on	Comes on	Click here
P0A7A-324	Generator Inverter Performance	- Inverter cooling system - Cooling fan system - Power management control ECU - Inverter with converter assembly - Hybrid vehicle generator assembly - Hybrid vehicle motor assembly - Generator cable - Motor cable - Inverter water pump assembly - Wire harness or connector - PCU fuse	Comes on	Comes on	Click here
P0A7A-325	Generator Inverter Performance	Inverter with converter assembly	Comes on	Comes on	Click here
P0A7A-344	Generator Inverter Performance	- Hybrid vehicle generator assembly - Generator cable - Inverter with converter assembly	Comes on	Comes on	Click here
P0A7A-517	Generator Inverter Performance	Inverter with converter assembly	Comes on	Comes on	Click here
P0A7A-518	Generator Inverter Performance	- Inverter with converter assembly - Hybrid vehicle generator assembly - Hybrid vehicle motor assembly - Wire harness or connector	Comes on	Comes on	Click here
P0A7A-522	Generator Inverter Performance	Inverter with converter assembly	Comes on until DTC is cleared	Comes on	Click here
P0A7A-809	Generator Inverter Performance	Inverter with converter assembly	Comes on	Comes on	Click here
P0A7A-810	Generator Inverter Performance	Inverter with converter assembly	Comes on	Comes on	Click here
P0A7A-811	Generator Inverter Performance	- Inverter with converter assembly - Hybrid vehicle generator assembly - Hybrid vehicle motor assembly - Wire harness or connector	Comes on	Comes on	Click here