check engine light on, cost $110 diagnostic fee, then goes off by itself!

Discussion in 'Generation 1 Prius Discussion' started by 2003prius, Jun 13, 2011.

  1. 2003prius

    2003prius New Member

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    Hello Everyone,
    I'm brand new to the chat forum, so bear with me!

    I have a 2003 Prius that I absolutely love! I have just under 82,000 miles and it only had approximately 95 miles on it when I leased it in Feb. 2003. (I'll never lease again!) So, when the lease matured, I didn't want to part with it and the car's been basically problem free.
    Just the standard oil changes, tire rotation, replacing tires.

    On Friday, June 3rd, my check engine light went on, I immediately pulled over, checked the dipstick, but all was well. I drove carefully/slowly home since according to the manual it states, "take to dealer."

    On Monday, June 6th, I took it to the dealer and paid $110 for a diagnostic fee and was told:

    "You have a malfunctioning sensor in the tailpipe which is stuck in the open position and it will cost $1500 to replace, wish I had better news for you."

    I asked what would happen, would I still be able to drive home, would the engine blow up, etc. All the service manager said was, "Well, it will affect the performance of the car and the gas mileage."

    As of Friday, June 10th, miraculously the check engine light went off by itself and has not come back on. PHEW!

    AND it has NOT affected my gas mileage, I'm getting anywhere between 48-50 mpg, which is what I usually get!

    Anyone know what's going on other than I got screwed out of $110. However, atleast I didn't have to part with $1500.

    As much as I love hybrid technology, that's the one thing that'll get you is the repairs. God, I pray the battery lasts another 8 years or more!

    Thanks everyone!
    Karen
     
    #1 2003prius, Jun 13, 2011
  2. JimN

    JimN Let the games begin!

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    Karen, welcome to the site. You are now the new poster child for the "Always get the codes in writing" campaign. Posting the codes here would get you an avalanche of expert help.

    If you aren't going to buy a ScanGauge II for the instrumentation then buy it for the code reader. It'll pay for itself in a couple of uses.

    I'm not a mechanic but I suspect your problem is more toward the BS side than the Catastrophic Failure side as you report no other symptoms.

    Generally the CEL will not stay lit but will turn off after 3(?) reboots but the code is stored. Visit one of the auto parts stores that advertize free code reading & let us know what it is.
     
    #2 JimN, Jun 13, 2011
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  3. Daves09prius

    Daves09prius Active Member

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    Welcome to the site!
    Next time the CEL comes on save yourself the money and, go to Advanced Auto, or Pepboys, most of the time they will let you use one of their scan-tools and you can pull and clear the code yourself. Then post the code here on the site and ask questions. You can also search for the code on Google. You'll know then if it's something simple like a loose gas cap, or something that you absolutely need to go to the stealership - I mean dealership for repair.
     
    #3 Daves09prius, Jun 13, 2011
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  4. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Hi Karen,

    Does the repair invoice show the DTC (diagnostic trouble code) logged by your car?

    Without that, my guess is that the hydrocarbon absorption chamber valve located upstream of the catalytic converter is sticking. Then the valve freed itself so that the check engine light went off. If my guess is correct, the valve will bind up again and you'll have a repeat of the problem.

    A short-term fix is to lubricate the valve with high temperature grease. A long-term fix is to replace the HCAC and catalytic converter, and this part is quite expensive so $1,500 is about right as a repair quote.

    Failure of the HCAC valve has zero impact on driveability or mpg. However it will worsen the car's startup exhaust emissions.
     
    #4 Patrick Wong, Jun 14, 2011
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  5. JimN

    JimN Let the games begin!

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    There's your avalanche of expert help. Listen to Patrick.
     
    #5 JimN, Jun 15, 2011
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