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  1. #1
    Join Date
    May 2006
    Location
    Houston TX
    Posts
    185

    Default 1999Xc - Bad News for Catalytic Converters

    Seems Volvo has decided to discontinue a catalytic converter for the 1999 xc70. (127,000) As far as I am aware there are no direct replacements. It keeps throwing the check Cat code - best to just ignore it? Short of removing the cat altogether and deal with the results ? I do I fool the ECU? Car runs great actually, better gas mileage in town with the light on.

  2. #2
    Join Date
    Apr 2003
    Location
    Devon PA
    Posts
    11,409

    Default

    If it's a cat EFFICIENCY code, ignore it if it only pops up 3-4 times a year.
    I have that code, had it for years.
    I bought a 60K mile used cat now several years ago just in case it finally really does go bad
    All emails please use: jrl1194 (at) aol.com

    2007 V70 2.5T White/Oak, 112K miles. My daily driver and GORGEOUS
    2000 V70R wife's. Won't sell, now at 148K miles !! and still (almost) perfect.
    2000 S70 GLT SE with 29,000 miles!!! A time capsule, V70R front bumper, Volans, etc. SOLD!!! (I Will regret selling this!)

  3. #3
    Join Date
    May 2015
    Location
    Northeast
    Posts
    1

    Default

    I have a 99 and I get a cat code every couple of weeks but mileage is still 21 mpg in the city, have 169,000 miles on it and still runs strong

  4. #4
    Join Date
    May 2006
    Location
    Houston TX
    Posts
    185

    Default

    Quote Originally Posted by Windryder View Post
    I have a 99 and I get a cat code every couple of weeks but mileage is still 21 mpg in the city, have 169,000 miles on it and still runs strong

    I reset the codes a few months ago - its back again - I don't recall seeing the word efficient used anywhere - is there something I should look for?

  5. #5
    Join Date
    May 2006
    Location
    Houston TX
    Posts
    185

    Default

    Just cleared the code- yes it did have the effenciecy code- what is causing this? I can think of only the upstream and downstream sensors. I can ignore the light but if something serious comes up - I won't know as the check engine light is already on

  6. #6
    Join Date
    Apr 2003
    Location
    Devon PA
    Posts
    11,409

    Default

    As I said don't worry about it as long as it takes a awhile to come back.
    I bought our 2000 V70R with 57K miles a long time ago (we still have that one).
    In its records apparently the same thing happened at 47K miles so under warranty the dealer replaced everything, CAT and both 02 sensors.
    That lasted for almost exactly the same amount of miles, this time 40K and at a bit over 100K I got the code again.
    Knowing that it already had new parts I had a chat with my Volvo service manager.

    He said he's seen this a lot and there doesn't seem to be a real answer for a permanent sure. It happens to certain 99 and 2000 AWDs, why, who knows. The tolerances built into the system are too just too tight.
    So, again I state again, don't worry about it unless it comes right back in 150 miles.
    Buy a cheap code reader and just clear the code when it pops up.
    It's been over 30K miles since this started over 3 years ago and nothing on my R has changed, every 1000-1500 miles or so it pops up and I just clear it
    All emails please use: jrl1194 (at) aol.com

    2007 V70 2.5T White/Oak, 112K miles. My daily driver and GORGEOUS
    2000 V70R wife's. Won't sell, now at 148K miles !! and still (almost) perfect.
    2000 S70 GLT SE with 29,000 miles!!! A time capsule, V70R front bumper, Volans, etc. SOLD!!! (I Will regret selling this!)

  7. #7
    Join Date
    Dec 2009
    Location
    GA
    Posts
    1,333

    Default

    Quote Originally Posted by tranmkp View Post
    what is causing this? I can think of only the upstream and downstream sensors.
    You are correct - the ecu compares the voltages from the front and rear o2 sensors - (higher output voltage = more O2 with first generation sensors). The front section of the convertor is supposed to chemically change HC, CO and O2 into H2O and CO2. If the rear sensor signals too much O2 present - the ecu thinks the convertor is not working properly. I can't recommend this because it is tampering with an emission system but there is a work around, a rig that people use to fool an ecu. Google "o2 sensor extender"

  8. #8
    Join Date
    Apr 2003
    Location
    Devon PA
    Posts
    11,409

    Default

    Also the consequence of one of these Volvos is they're usually quicker.
    Our black one was always (and still is) the fastest of all the 2000s I've ever owned and quite a few, around 25=30 over the years.
    Probably runs just a hair richer.
    All emails please use: jrl1194 (at) aol.com

    2007 V70 2.5T White/Oak, 112K miles. My daily driver and GORGEOUS
    2000 V70R wife's. Won't sell, now at 148K miles !! and still (almost) perfect.
    2000 S70 GLT SE with 29,000 miles!!! A time capsule, V70R front bumper, Volans, etc. SOLD!!! (I Will regret selling this!)

  9. #9
    Join Date
    May 2006
    Location
    Houston TX
    Posts
    185

    Default

    update - after resetting light - it comes back in a day or two - thoughts?

  10. #10
    Join Date
    Apr 2003
    Location
    Devon PA
    Posts
    11,409

    Default

    Day or two, start replacing parts
    All emails please use: jrl1194 (at) aol.com

    2007 V70 2.5T White/Oak, 112K miles. My daily driver and GORGEOUS
    2000 V70R wife's. Won't sell, now at 148K miles !! and still (almost) perfect.
    2000 S70 GLT SE with 29,000 miles!!! A time capsule, V70R front bumper, Volans, etc. SOLD!!! (I Will regret selling this!)

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