Inverter Replacement

My 2003 Prius has just 73,000 miles. Last year, one of the cells in the hybrid battery was busted, and they replaced the whole battery under warranty. So this morning, when the hybrid system failure light came on and the power cut out, I assumed I was dealing with a recurrence of the same issue. (Error codes below.)


I was wrong. The rep at the dealer now tells me that the inverter has failed, and needs to be replaced. He quoted a price of ~$4,200, which made my jaw drop. Didn't expect an integral part to simply fail like that this early in the car's life.

Does this sound like a reasonable diagnosis of the problem? Is the cost estimate in line? Do I have other options - that is, can the repair be done in an ordinary shop? Are there used or rebuilt inverters on the market?

Thanks, in advance, for any guidance anyone can offer.

These are the error codes reported by the dealer:


P3125 - Converter & Inverter Assembly Malfunction

289 Motor Inverter Current Sensor Malfunction. Open in inverter current sensor (V phase sub sensor)
292 Motor Inverter Current Sensor Malfunction. Open in motor inverter current sensor (V phase main sensor)

 

Thank you, Patrick - that's quite helpful.

I think this may not be the right project for me to begin a DIY approach - but I'll start hunting down an inverter. Anyone have tips on finding an experienced independent Prius tech?

And from some other threads in the forum, I see that the inverter pumps are sometimes the underlying problem. Is it worth replacing that, too?

 

A quick update, for other Prius owners with similar problems.

I wasn't able to find any independent tech willing to tackle the repair; they all pointed me back to the dealer. I talked with Toyota Corporate, who were initially quite sympathetic and intimated they might help, but ultimately decided that since I'm a few months beyond the hybrid warranty, I'm on my own.

But all is not lost. The dealer has agreed to perform the work if I furnish a salvage part, and their labor is surprisingly reasonable - less than 20% of the initial estimated cost. So I bought a $500 inverter from an '02 Prius with 78k miles off of eBay, and I'm hoping for the best. Since an inverter failure (with a perfectly functional pump) seems to be fairly unusual, I'm willing to bet that a salvaged inverter will have a decent amount of life left in it.

I've loved driving my Prius. And as frustrated as I am to have a key part like this simply fail, with no warning, while driving down the road, I'm hoping to keep on driving it for a while yet.