P0420 on 2007 Prius

The dealer says I need to change the catalytic converter and the good news is that it is all under warranty. (65,000 miles on 2007 Prius).

I'm wondering if I should do the repair.

The backstory: On a recent road trip, I found myself on a very steep hill. Going up, the car put itself into the B mode and I made it up though the car struggled some. Less than 1/2 an hour later, I noticed that the check engine light was on. Shoot! I was 8 hours away from home in a far away from civilization location.

Luckily, the next morning I started up the car and the light was no longer on. A few days later, I drove the 8 hours home.

Two days after I returned, the light came on again and has remained on. I went to Auto Zone and the pulled the code as P0420 and printed out the possibilities for me. I saw here and in my manual that if that code was accurate, it was catalytic converter/air sensor emissions related and should be covered by warranty, so headed to dealer.

Dealer charges $109 for diagnosis, which I balk a bit about. They need to charge me to tell me what is wrong with the car they made and sold me? Seems ethically wrong, even though it's standard procedure. Got the guy to state that the fee would be waived for anything under warranty. I knew the code, but didn't tell them about my own investigation.

They later came back to ask me when the car had run out of gas as that was in it's history. That was last summer, and it struck me as odd that something so sophisticated as to record my running out of gas could not also document the time or mileage when that occurred....

Later he returned with three pages of print out of info stored on my car and said they would order a new catalytic converter, everything under warranty, wait for their call. They also reset the light.

So my hesitation is, if the sensor was reset and it doesn't go off again, couldn't this be a fluke? Or am I really just better off getting the catalytic converter changed now before I pass the 80,000 mile marker?

Thoughts?

 

Hmmm. Since the dealer doesn't have any cost either, I'm not so quick to follow the "let the dealer do as they will" line of thinking. Perhaps replacing the catalytic converter is what is easiest and most likely to make most customers satisfied, but I'm more of a "if it isn't broke it, don't fix it" kind of gal. What does it say about a car if it needs a new CC at 65,000 miles? Is this common with other Prius Gen II owners?

Since the car threw the code under duress, if the code is cleared and doesn't reappear, shouldn't that indicate that it was an anomaly? Furthermore, just prior to the trip I passed the state emissions test just fine.