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Gold Hills Posse 4×4 Club · Folsom, CA

Smog of Death

  1. k-jeep Member Joined: May 2009
    #129 May 2023, 12:32 AM

    Long story short, I got the dreaded P0420. New cats, new O2 sensors, new thermostat (got a different code for that one). Everything passes the smog check on my scanner except the oxygen sensor test will not complete. I’ve driven a lot of miles and tried the 40-60-40mph tip. Besides registering in a no smog county/state, are there any other tips to get the oxygen sensor test to complete so I can pass smog?

    Next will be to drop it off at Folsom Jeep if I can’t figure it out.

  2. Lynda and Guy Member Joined: June 2021
    #229 May 2023, 2:19 AM

    OH man! Sorry to hear this! 😤

    Let us know how it goes.

    Buck is fighting a lot of red tape for his rig as well.

    L 👧

    "No beans!"
  3. Jeff_R Member Joined: October 2016
    #329 May 2023, 7:07 AM

    If you have to take it to a shop, take it to Applegate garage. The owner Zach is awesome. Check out their reviews online. Plus he is an off road guy. Call the shop and ask to talk to Zach and tell him what you've done. He will give you tips and that way you can get a feel for him and his shop before going there, should you do need to take it in. Tell him that I recommend you.

    Jeff and Kathy Root
  4. BKGM Jeepers President Joined: June 2003
    #430 May 2023, 2:12 AM

    Getting the last code to clear took me more than 40 miles of driving on back country roads, but it eventually registered all green.  I drove around Loomis, Lincoln, Auburn area.  Their back roads seemed to be the best speed for my criteria to register.  I just kept the reader in my jeep and checked it every 30 mins or so.

    Kathleen and Brad
  5. kris_olof Trailmaster Joined: October 2015
    #530 May 2023, 3:14 AM

    I use fast Freddy’s for smog at the shingle springs exit. O2 was the only thing that wasn’t ready. He sent me out on a short drive down north shingle road about half way to Lotous holding 40mph. Got back and it had worked.

  6. JohnDF Member Joined: July 2003
    #630 May 2023, 7:50 AM

    What Brad said... drive the crap out of it on the back roads.

    I used to wheel a lot. . .
  7. Brian Member Joined: February 2020
    #731 May 2023, 3:13 AM

    Yeah I drove for over a year without even knowing my o2 wasn’t running. The little ding check engine in the run position has been going off since I changed my battery I just didn’t know what it meant.

    Those instructions I sent you were done on green valley road.

    Thompsons Jeep was really cool about the whole thing and worked hard with corporate but mine was under warranty. New o2 sensors and pcm did nothing. Maybe luck was the final result of it passing.

    W6JLU
  8. k-jeep started this Member Joined: May 2009
    #831 May 2023, 5:37 AM
    kris_olof said I use fast Freddy’s for smog at the shingle springs exit. O2 was the only thing that wasn’t ready. He sent me out on a short drive down north shingle road about half way to Lotous holding 40mph. Got back and it had worked.

    Any specific RPMs or just regular driving? I’ll keep trying different things a little longer.

  9. k-jeep started this Member Joined: May 2009
    #931 Aug 2023, 8:22 AM

    Just thought I would post a follow up. I eventually passed smog. I disconnected and reconnected the PCM connectors and the O2 sensor test completed.

    Coincidence? Who knows, but something to try if you run into the same issue.

  10. Dale Clement Member Joined: June 2015
    #102 Sep 2023, 11:25 AM

    You gotta love modern technology

    Dale Clement
  11. Nubby Webmaster K6NUB Joined: February 2018
    #117 Sep 2023, 12:45 AM

    Crazy, but hey, now you are legal, lets wheel!

    Jamie & Damaris
  12. Lynda and Guy Member Joined: June 2021
    #1214 Sep 2023, 1:03 PM

    Welcome back!!

    L👧

    "No beans!"

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