Help on unusual symptoms p0a94-555

Generally here you replacing the thing on bottom of inverter under gold plate with lots screws . Good luck getting that plate off . Faster to change whole inverter

 

Nope. That's also called a DC/DC converter, but it's the one that drops voltage to 12 volts for the low-voltage system.

P0A94 is about the other DC/DC converter, the one that boosts voltage to 500 volts for the motor-generators.

It's inside the inverter assembly, and replacing the inverter assembly as a whole still is probably the much easier way to go.

The freeze-frame in the OP shows "Voltage before boosting" as 208 and "Voltage after boosting" as 207, which could be normal if the HV control ECU didn't want any boosting at the time, but would be a little disappointing if the system was trying to boost. In any case, the P0A94 code indicates the car can tell there's a problem there.

The car may not be completely immobile with the boost converter out of commission, but it won't be happy.

 

Yep another DC to DC converter anyway it is no cost effective to work on inverter . They're getting thrown out all over the country. Can probably find one you can have locally. That's not broken.

 

I know it'll plug up I just got an 05 I'll probably try it if it fails. The Gen 2 inverter is pretty stout I haven't had any fail yet.

 

And what is this the 05 inverter or you putting an 06 up in your 05?

 

The third Techstream image attached shows the SoC at 48%, so 3 bars sounds correct.

 

Around 8.2-8.4 V. It varies depending on ambient temperature and the condition/age of the module. In my experience, if you are able to charge to voltages higher than that, it indicates a depleted module. A module that exhibits that trait will probably also charge and discharge faster than the others.

Note: A module is made up of 6 cells. As the modules are sealed, it is not possible to do cell-level analysis.

 

Look at the freeze frame data and tell us what the detail/INF code is. That will narrow down the trouble shooting process for the P0A7A code.

 

It's 309 sub

 

They're saying this is isolation type fault business but apparently in MG or wiring etc .

 

Thank you. How many miles was the car driven after you changed the inverter?

Based on the freeze frame data, it appears the car was stationary and the engine was not running when the code was triggered. Can you please describe what you were doing with the car when the code triggered? Was the car in Ready?

There are not many parameters listed in the freeze frame data. It appears that the car was not driven after the previous code was cleared. The engine coolant temperature shows 0C which can not be correct. The +B voltage is 11.28V which is low. That is the reason I asked if the car car Ready. Have you tried clearing the trouble codes?

The troubleshooting procedure for P0A7A with the -309 detail code looks to be very simple. You check the wiring harness that runs between the HV ECU and the inverter. Here is a link to the repair manual, DTC 309 — 2005 Toyota Prius L4-1.5L (1NZ-FXE) Hybrid Service Manual | Operation CHARM