Replaced Inverter in 2013 prius and fixed codes for a day now throwing U0110 w/ check hybrid system

The error code U0110 has subcodes.
The problem is seen in the connections between the inverter and the power management control ECU (HV CPU).

Trouble Area:
Wire harness or connector
Inverter with converter assembly
Generator cable
Motor cable
Hybrid vehicle transaxle assembly
Power management control ECU
PCU fuse

 

Oddly, the same U0110 code just came up for somebody else, over here.

Because it's a U0 (SAE standardized) code, it uses an SAE standardized name, Drive Motor Control Module "A", for an item Toyota calls something else. My thinking is it refers to the MG ECU, located inside the inverter assembly.

But I wouldn't just charge in and replace that ECU. The U codes are communication codes; in this case, the power management control ECU under the dash (which handles both Hybrid Control and Cruise Control) is saying it can't communicate with the other ECU. The cause of the problem could be something in either ECU or in the wiring between them, so it pays to go through the troubleshooting steps and see what's really the root cause.

Regrettably, while there is a PDF file that can be found on the web of most of the repair manual, the actual full troubleshooting section for U0110 is one of the sections that got missed, so it may have to be found in the repair manual online.

Toyota Service Information and Where To Find It | PriusChat

if the inverter was just replaced, I would certainly double-check the electrical connections (chiefly the low-voltage, communication connections) before assuming anything needs replacement.

It looks as if the original inverter was replaced because of P0A7A and P0A94? Who did the replacement? You say the car was sold to you "as is", but was it reporting those codes at the time of sale?

Inverters failing with P0A7A and/or P0A94 are covered by Toyota for 20 years and unlimited miles, so for anybody else with those codes, the best move is probably to let Toyota do the replacement; then it's up to them to have the replacement working and free of trouble codes when you get the car back.

 

For anyone else who may search up this thread and have the same question, Toyota's 23TE02 and 23TE03 twenty-year, unlimited-mile coverages for certain inverter failures apply regardless of who owns the car, and even apply to salvage, total loss, true mileage unknown, or other similar titles. More information at this post.

So, if a car is having inverter trouble with any of the trouble codes referred to in those campaigns, do not pass GO, go directly to your friendly Toyota dealer and let them take care of it for you. No need to DIY and possibly end up with extra puzzles.