Replaced inverter : new issues codes etc

Hey all,

I recently replaced a faulty inverter with dc to dc failure. Car has done 225k kms...

Got a used replacement inverter and it worked ok for 10 minutes before warning lights and check hybrid system came on.

Cleared codes with mechanic, got it started and it drove fine until we turned it off and on again, after turning it on again, the car won't go into Reverse and only just limps forward.

Tried replacing with another used inverter and the same issue is happening.

Mechanic says it could be the gear box, but not entirely sure.

How can the car be driven ok with original inverter (with dc to dc fault) and then not Drive or go into Reverse after new inverter that appears to be working (ie charging the battery).

Here's my original long winded post:
Hello all, I'm in Brisbane, Australia. This is my second Prius and was loving it until recently the check hybrid system lights appeared.

I had noticed a bit of an issue when stopping at traffic lights, the petrol engine would sputter and sound like it was almost conking out before switching to the hybrid motor while stopped, but this never seemed to effect the driving.

Initially after the engine lights came on, I took it to Toyota service dealers and they told me it had codes P0A7F, P0A94 and P3604.

They told me it would need a new converter with converter G9200 49025 which they charge $5000 aud.

I said no thanks, and found a second hand inverter online and got someone experienced to install it, it ran ok for about 10 minutes before warning lights came back on.

The next day I turn the car on and the codes have disappeared, but the day after all the lights come on again, BUT this time the engine revs are higher than normal and the gear box shifter won't go into Reverse or Drive forward very much (limp mode?).

Towed it back to Toyota to have them re-diagnose again $, and they tell me the same story $$$$...

So I towed it to a mechanic who works on Taxi Prius' and he got it going again after clearing codes, but car does the same thing after I turned it off and on again. We tried installing another inverter from the parts supplier and still the same thing happened only this time the mechanic says the car is throwing codes P0A4D and P0A4C which he believes might be the gear box / transaxle assembly. Which is another big job $$$$ and no guarantee this will fix it...

I don't understand how the car can drive fine with broken inverter (dc to dc fault) on petrol engine (go into fwd and reverse) but install a different inverter that seems to work and have gear box issues.

Should I roll the dice or send to the wreckers?

 

Thank you for the replies,

Will be checking the wiring tomorrow.
We pulled initial replacement inverter out last week, and replaced with another one from the parts supplier.
It seems to run ok with the broken inverter (no power from Hybrid but it goes into drive/reverse ok) but as soon as we put a working inverter that powers the hybrid system it won't engage ICE and won't go into reverse for some reason. The mechanic was able to get it going for 5 mins, but won't work after we turn it off and on again.
Cheers