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Older Toyota Avalon (pre-2000) Maintenance and Repair

I had the check engine light come on in my 2000 Toyota Avalon XLS (85000 miles) and I took the car to autozone and my local mechanice both of whom diagnosed the error code as P0420 - Catalyst System Efficiency Below Threshold ( Bank # 1). My mechanic said this problem was common on avalons and attributed the reason to the catalytic converter failure. He said it would cost me $ 630 /- for parts + $ 100 /- for labour to replace. Which In my opinion is too high. Has anyone faced a similar issue before ? There is no effect on the performance or MPG of the car. What could've gone wrong and how much will it cost me to fix ? Is it really the Cat conv or the O2 sensor ? Incase its the cat, can I buy one from junkyard ? Also will it have any effect on the car in the long run ( besides failing the DMV Inspection) if I continue to drive without addressing this issue.


  • its been more than 12 days and not a SINGLE reply...and I was thinking this was the most active avalon forum on the web !!!!

  • patpat Posts: 10,421
    It's not unusual for a single question hanging out in a discussion all by itself to be missed. You might try reposting in the Toyota Avalon 2004 and earlier discussion. If no one there can help, you could also try either the Ask The Community feature on the right side of the page or the Quick Technical Questions discussion which is over on the Maintenance & Repair board.

    It's usually better to post in a discussion where people are already reading and posting, more people will see it that way.

    Hope this helps!
  • Thanks Pat..I'll surely try the options mentioned by you
  • bill5105bill5105 Posts: 1
    I also hav a 2000 Avalon XLS q128,000 miles with the same P0240 issue. I don't see any response to your question. What was your outcome?
  • the code which was there on my car was P0420 which went off on its own and then i got a new code P0170 which went away after i replaced the mass air flow sensor (MAF).
  • I'm a little late to this post but I have an 01 Avalon XLS with 250,000 miles on it and at 120,000 miles my light also came on. My mechanic gave me the same diagnosis but I've been able to pass inspection every time as long as the light is off which I typically do by unhooking the battery and hooking it back up which resets the vehicles system and takes away any check engine lights for a few days.
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