+ Reply to Thread
Results 1 to 14 of 14
  1. #1
    Registered Member
    Location
    Selden, NY, United States
    Member No: 73453 andrewash is an unknown quantity at this point andrewash's Avatar
    Join Date
    Apr 2003
    Posts
    800
    Rep Power
    0


    Yes | No

    Catalytic converter error code - options?

    1998 1.9 Roadster in shop now - check engine light on, code says error message from catalytic converter

    Light came on last weekend and we put over 600 miles on the car with no problems. Took car to shop today (first chance I had to do so as we were away)and they said probably need new cat = $1,400.

    Any chance it is just a sensor problem? What would we experience while driving if the cat were 'bad'? How long can I postpone the expense and would I do any damage if I did postpone? Comments? Suggestions?Read "Through The Esses" on RaceFansTV.com

    ashautomobilia.com

    TheRaceSite.com

    dailysportscar.com



  2. #2
    Registered Member
    Location
    Selden, NY, United States
    Member No: 73453 andrewash is an unknown quantity at this point andrewash's Avatar
    Join Date
    Apr 2003
    Posts
    800
    Rep Power
    0


    Yes | No

    What does code P0420 Tell you???


  3. #3
    Registered Member
    Location
    Spring Green, WI, United States
    Member No: 146192 s-retire is an unknown quantity at this point s-retire's Avatar
    Join Date
    Oct 2006
    Posts
    706
    Rep Power
    0


    Yes | No

    Re: Catalytic converter error code - options?

    From the most common reports here, the code most likely indicates a failure of the primary O2 sensor. The O2 sensor is a wear item and does need periodic replacement. I think BMW recommends every 100,000 miles, but more frequent replacement may be required.

    Replacing the cat will not resolve the issue and the code will come back. Not replacing the sensor may lead to eventual failure of the cat.

    Good news is the O2 sensor is a lot less money.

    Use the search function here to get more info.

  4. #4
    Registered Member
    Location
    Selden, NY, United States
    Member No: 73453 andrewash is an unknown quantity at this point andrewash's Avatar
    Join Date
    Apr 2003
    Posts
    800
    Rep Power
    0


    Yes | No

    Any shade tree mechanics in Suffolk County?

    Near Port Jefferson / Setauket / Selden area? Someone who might walk me through how to replace the sensor???
    Read "Through The Esses" on RaceFansTV.com

    ashautomobilia.com

    TheRaceSite.com

    dailysportscar.com


  5. #5
    Registered Member
    Location
    Selden, NY, United States
    Member No: 73453 andrewash is an unknown quantity at this point andrewash's Avatar
    Join Date
    Apr 2003
    Posts
    800
    Rep Power
    0

  6. #6
    Monolith
    Guest
    Location
    , ,
    Member No: Monolith's Avatar


    Yes | No

    General How To Link

    For an e30, but basically you need to spray the pre-cat sensor with penetrating liquid for a few days before attempting to break it free (the pre-cat sensor is the sensor in the exhaust nearest the engine).

    I'll see if I can find an M44 DIY.



    e30 O2 Sensor DIY

  7. #7
    Monolith
    Guest
    Location
    , ,
    Member No: Monolith's Avatar


    Yes | No

    Another general information link


  8. #8
    Registered Member
    Location
    Selden, NY, United States
    Member No: 73453 andrewash is an unknown quantity at this point andrewash's Avatar
    Join Date
    Apr 2003
    Posts
    800
    Rep Power
    0


    Yes | No

    Update

    A friend with years of experience and a lift in his garage (he fixes cars evenings and weekends. Funny how an old mind like mine can forget he was always a resource I could avail myself of) will handle the sensor changes when needed.) I say when needed because the car is running like a top now, no signs of any check engine lights or operating problems of any kind.

    Codes were cleared by first shop and so far - knock on my wooden head - the car is running like new.

    Funny but, when the transmission was removed to replace the seals, he disconnected the battery. (I know because I had to input the code in the radio). For a day or two after the tranny fix, the car ran well but just didn't seem to be 100%. I've read that when the battery is disconnected, the car needs to 'relearn' how to run properly and that comes with time. Right now it seems to be that time!

    Again, if the light comes on again, or the car's performance seems to diminish, I will take the car to my friend and go with replacing the sensors (both of them). If, after that, anything else seems amiss I will replace the cat (and reuse my new sensors in the new cat).

    Thanks again for all the advice, information and support!!
    Read "Through The Esses" on RaceFansTV.com

    ashautomobilia.com

    TheRaceSite.com

    dailysportscar.com


  9. #9
    Mark
    Guest
    Location
    , ,
    Member No: Mark's Avatar


    Yes | No

    Re: Update

    I've been driving with the same error code for at least a year now. When i researched it my conclusion was a bad cat. I can normally go for some variable length of time before getting the code again (normally a number of hours). I then clear it and keep going. Seems to run fine.

  10. #10
    Registered Member
    Location
    , CNJ, US
    Member No: 90386 Monolith is an unknown quantity at this point Monolith's Avatar
    Join Date
    Oct 2003
    Posts
    404
    Rep Power
    0


    Yes | No

    Read Tim's Thread Below

    Link for future reference:

    Tim's Thread on Cat Efficiency Error

    Fixing the code (changing the precat O2 sensor) should give you better gas mileage and performance.

  11. #11
    ibralow
    Guest
    Location
    , ,
    Member No: ibralow's Avatar


    Yes | No

    Re: What does code P0420 Tell you???

    Went through this on my 96 1.9. After 2 years of trying "other" recommended fixes. Replaced both o2 sensors, replaced cat (because here in Jersey, you can't pass state inspection with a check engine light on)and of course had to go OEM, because the aftermarket ones WIlL NOT work with the obd system (I know this because I first tried an aftermarket cat). After finally giving in and installing oem, I have cleared the P0420 code.

  12. #12
    Robert Platt Bell
    Guest
    Location
    , ,
    Member No: Robert Platt Bell's Avatar


    Yes | No

    Which cat code? There are more than one.



    On my 2.8s, both cars did the "catalytic converter efficiency below threshold" error and in both cases, replacing the primary oxygen sensors was the fix.

    Cats rarely wear out.

    Again: Just because a part is mentioned in an OBD II code DOES NOT MEAN the fix is "replace named part".

    For example, "Oxygen Sensor out of range" usually means a crack in the intake elbow.

    Any mechanic who immediately says "replace the cat" is not a very good mechanic.

  13. #13
    Robert Platt Bell
    Guest
    Location
    , ,
    Member No: Robert Platt Bell's Avatar


    Yes | No

    P0240=Catalyst System Efficiency Below Threshold


    I suspect you wasted money on the new catalytic converter.

    It was most likely the oxygen sensor.

    But it is fixed, nevertheless.

  14. #14
    Robert Platt Bell
    Guest
    Location
    , ,
    Member No: Robert Platt Bell's Avatar


    Yes | No

    Typo: P0420

    I meant to say P0420. Too much 420 on my mind, apparently.

    See link for more info.

+ Reply to Thread


Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

     

Bookmarks

Posting Permissions

  • You may post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
1e2 Forum