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PO420 code

Discussion in '1st Gen. Tacomas (1995-2004)' started by allred27, Nov 13, 2008.

  1. Nov 13, 2008 at 8:35 AM
    #1
    allred27

    allred27 [OP] Member

    Joined:
    Oct 20, 2008
    Member:
    #10088
    Messages:
    12
    hey guys, my check engine light came on last night, I checked it and got the "PO420 Catalyst efficiency below threshold"

    what would it most likly be? the catalyst or the O2 sensor(s)? Or could it be something else?

    I just did a tune up, new plugs, wires, cap, rotor, synthetic oil

    it's a '96, Tacoma 4x4, 2.7, 183K miles

    Thanks
     
  2. Nov 13, 2008 at 11:05 AM
    #2
    ryanyoshi

    ryanyoshi Member

    Joined:
    Oct 23, 2008
    Member:
    #10182
    Messages:
    7
    Vehicle:
    '03 White Tacoma
    I just recently had that problem. For me it was due to an installation of a aftermarket catalytic converter since somebody stole my stock one. I'm pretty sure that it is your cat. and not your sensor. It's expensive to replace with a factory one. It'll be less than half the price to get an aftermarket cat. and an O2 simulator from URDUSA.com. Thats what I did and now my truck runs perfectly with not engine light. Hople this helps.
     
  3. Nov 14, 2008 at 7:58 PM
    #3
    tacotoe

    tacotoe Pastry Chef

    Joined:
    Nov 25, 2007
    Member:
    #3593
    Messages:
    442
    Nebraska
    Vehicle:
    `01 DBL Cab TRD
    Gibson Cat-Back Exhaust
    I had the same code (s) several months ago. I first replaced the front O2 (AFRM) sensor but the light came back on, then I bought some MAF cleaner, along with a can of TB cleaner and used them, then got a3?? code which was a TPS code (truck went into limp mode) then replaced the rear O2 sensor along with the TPS and the Light has been off every since. Tomorrow afternoon I will try to find pictures to post of the O2 sensor and TPS replacement but no guarantees as that particular camera`s lcd went out, I think I have them downloaded though.
     
  4. Nov 18, 2008 at 10:29 AM
    #4
    allred27

    allred27 [OP] Member

    Joined:
    Oct 20, 2008
    Member:
    #10088
    Messages:
    12
    Finally had some time to work on my truck. I wanted to look at the cat before I ordered a new one, so the owner before me just welded a new one on, it's not even the correct size, the cat's ends are 1/4" bigger then the exhaust pips, they just filled in the difference as they were welding.
    So it looks like I only have to options;
    1. cut off the cat and weld a new one back on
    2. replace the exhaust system
    So if I put a new exhaust system on, which header? And exhaust system should I get? I'm looking for power and sound.
    Thanks
     
  5. Apr 14, 2010 at 1:58 PM
    #5
    01dubb

    01dubb New Member

    Joined:
    Mar 10, 2010
    Member:
    #32957
    Messages:
    4
    Gender:
    Male
    First Name:
    Brian
    Chicago
    Vehicle:
    01 prerunner
    Chrome Step rails, 800 watt 8 inch pioneer subwoofer, 800watt pioneer mono amp, Kenwood 7inch dvd Navigation,
    With that many miles on you truck its gonna be the cats that are throwing the code. Putting an aftermarket cat on will only be a temporary fix for the problem. It will come back on within 5000 miles or so if that. The toyota one will cost ALOT more but will be the right fix for it. I had the same problem on my 01 V6 and its almost 800 for the pipe with the two cats in it.
     
  6. Apr 16, 2010 at 7:25 PM
    #6
    tacotoe

    tacotoe Pastry Chef

    Joined:
    Nov 25, 2007
    Member:
    #3593
    Messages:
    442
    Nebraska
    Vehicle:
    `01 DBL Cab TRD
    Gibson Cat-Back Exhaust
    probably close to 15,000 miles past and after changing both O2 sensors and the TPS, no more PO420 code. so it is not necessarily the cats as some would have led me to believe.
    2001 DBL CAB V6 170,00 miles
     
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