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Intermittent Ck Eng Lt

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by davidj08, Jun 8, 2014.

  1. davidj08

    davidj08 Junior Member

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    Our 2008 with 110,000 mi is intermittently displaying CEL. First appeared about 3 wks ago. I took gas cap off and then put it back on and let car sit overnight. Next day and for 10 days no CEL. Then one mornng, at first start, CEL reappeared. Repeated gas cap process that night. CEL disappeared for 6 days. Then CEL came on in middle of day after car had been started and stopped 3 times. Repeated gas cap process that evening with no success. Did the gas cap thing one more time, last night, and today the CEL is off. First time CEL came on was right after a fill-up. Subsequent CEL's have had no relationship to refueling. Car has been nearly flawless for 68 months. Engine coolant pump changed @ 75k. Aux batt changed 24 mo ago. Any ideas?
     
  2. northwichita

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    Find a local auto parts store that does free CEL checks, Autozone for example , and report back .
     
  3. nh7o

    nh7o Off grid since 1980

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    Yes, get the code read. The gas cap may just be a red herring.
     
  4. exstudent

    exstudent Senior Member

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    Hopefully its a bad 3-way coolant control valve on the hybrid coolant loop. If the Diagnostic Trouble Code (DTC) says P1121, and the car was initially registered in and stayed in a CARB state, you have warranty coverage. 10 year/150,000 mile emission and hybrid battery warranty for CARB states. The above failed part affects emissions. Mine was replaced under warranty, in January 2014, at 121,500 miles.

    Many people who have had this part go bad, reported that the check engine light comes on for minutes/hour(s), then may go away, and may come back on again (after hours or days; no pattern, just random). All the while, the Prius drives normally, with no unusual noises.

    Here's and article about P1121 by Luciouis Garage. LINK
     
  5. davidj08

    davidj08 Junior Member

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    Sorry for the delay in responding with code. Exstudent, you described problem perfectly and your diagnosis was 100% accurate. Thank you. It was code P1121 and the coolant flow control valve needed replacement. I took vehicle to an independent shop for diagnosis and repair. I've been using this place for 5 yrs with great success. They told me they talked with local Toyota dlr (to obtain the part) who said item was not covered under warranty. Our Prius is and always has been a CA car, so 180 mo/150k mi emissions performance and defect warranties apply. So, something is not right. I'll pursue this matter with the Toyota folks in Torrance. Total repair was $396. Thanks again Exstudent.
     
  6. davidj08

    davidj08 Junior Member

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    Talked with "Daniel" at Toyota Customer Svce in Torrance earlier today. He told me the coolant flow control valve was not covered under any emissions warranties. It was covered only under the general warranty applicable to the entire car. Absent any documentation to the contrary, I must accept this verdict. Exstudent, you were very fortunate.
     
  7. JC91006

    JC91006 Senior Member

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    Maybe Exstudent can share his receipt for his warranty repair? Surely that's evidence it was once covered under warranty.
     
  8. exstudent

    exstudent Senior Member

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    No problem sharing the receipt if wanted. Just private message me with an email address to send the receipt as a PDF.
    However, I still foresee Toyota giving David a big stink by saying their dealership network was unable to verify the DTC, since David went to an independent shop.

    I guess the local dealership/service advisor is aggressive in wanting warranty work. I simply walked in describing the problem (intermittent check engine light). OBDII code readers said P1121. Handed them a copy of the TSB that deals with this 3-way coolant control valve. This same TSB also states this 3-way valve is only covered under the 3year/36,000 mile warranty. However, I insisted that it should be covered under the longer emission warranty because the valve can cause the engine to turn-on/stay-on unnecessarily, causing excess emissions. Another PC member in the Santa Monica area (I believe) got this valve covered under emissions warranty too. I guess some dealerships are more warranty work aggressive than others; not only did they do the 3-way coolant control valve, but they also did the steering shaft recall.
     

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  9. davidj08

    davidj08 Junior Member

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    Exstudent, I appreciate your generosity and willingness to help. It's an example of what makes the Prius community so outstanding. And thanks for including the TSB in your latest note. Per the TSB the applicable vehicles are '04 thru '07 produced before a production change. Since mine is an '08 and no doubt produced after the production change, I think I'm on weak ground trying to extrapolate your experience to my situation. Though I did use an independent shop, the old part is on hand and I could present it to Toyota for their inspection. Assuming they would agree the valve is faulty, in my mind it comes down to Toyota covering something well above and beyond their stated warranty limits. While I've successfully pursued similar matters with Toyota and years ago with Acura and prevailed, I don't believe my chances are good this go 'round. What bothers me is how they could arrive at the conclusion that an integral part of the CEL system is not part of the emissions control system. If that part fails, at a minimum my emissions system is compromised. If I were to drive into smog inspection station with the CEL illuminated and ask for a smog ck, they'd fail the car because the CEL is lit. Why it's only convered under the 36/36 general warranty is a mystery to me, but I think I'm going to have to accept it. Thanks again for sharing everything.