Question about 2001 Chevrolet Tahoe

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After service engine soon warning, diagnostics performed and then all o2 sensors were replaced. Service engine light came back on and diagnostics keeps saying 2 o2 sensors are bad, but they test 100%. Mechanics cannot find problem and warning back on again. The truck seems to be running fine otherwise, at 66,000 miles. The recommended 60,000 mile service was all done, including cab filter and all other filters replacement. Any suggestions would be appreciated.

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  • jbetz8 May 24, 2009

    The sensors were retested, and the computer indicates 2 are bad, but tests of the sensors says they are operating at 100%. The service center has done this 3 times, and cannot find anything else wrong; the warning light just keeps coming back on.

  • jbetz8 May 24, 2009

    I hope so. I will have to take it back to the service center to know. Thank you.


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Thanks for using FixYa. If all the o2 sensors were replaced but still the diagnostics says that 2 o2 sensors are bad then I believe they are either not placed properly or have gone bad again. You need to take it back to the service center and tell them to check it as they should do this free of charge.

Please do accept the solution and revert for further assistance.


Posted on May 24, 2009

  • Rylee Smith
    Rylee Smith May 24, 2009


    Thanks for your reply. Usually this issue is caused by the o2 sensors going bad but as you said they test 100% then it may have something to do with the fuel filter replacement, I believe you can go to AutoZone and have them check it for free. If that’s not the issue then it indicates that the computer is seeing slippage when the TCC (torque converter control) is energized. It is seeing a different between engine RPM and transmission RPM which would indicate that the torque computer is slipping.

    Please do accept the solution and revert for further assistance.


    Please do accept the solution and revert for further assistance.



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