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Thread: Catalyst effeciency (Bank2 O2 sensors) disable on 96 Vortec "Black Box" PCM

  1. #1
    Potential Tuner
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    Catalyst effeciency (Bank2 O2 sensors) disable on 96 Vortec "Black Box" PCM

    Anyone know if there is a set of OBD-II commands that can be used to disable the rear O2 sensors and Catalyst Efficiency checks on the 96-97 "Black Box" PCM without using tuning software to rewrite the entire flash?

    I have a 96 K1500 Suburban I picked up that has had the Cats cut out already. Rear O2 sensors are still there and functional, but without the Cats, I get a constant on MIL and P0430 Catalyst Efficiency code.

    I would like to just disable the Cat efficiency checks, as I live in Indiana and don't have to worry about emissions testing. I have an ELM327 device, and I know I can use it to issue commands to the PCM. I know I can't use it to rewrite the flash, however, I have had very little luck finding any information on what sort of commands can be used. I don't really have any interest in spending $500+ on tuning software just to disable a DTC code, especially if I have to spend another $100+ on top of that plus a weekend of my time to do an LS1 (0411) PCM swap. I'm not looking to turn it into a performance vehicle, I only picked it up for towing a large camper, hauling scrap, and the occasional longer trip with the family.

    So, I'm hoping someone on here might be able to tell me if it's possible to disable specific DTC/MIL checks using only OBD-II commands, and if so, point me to the necessary commands to do so.

    Alternately, can anyone point me to a shop in the North Central Indiana area that has the ability to do this and won't charge an arm and a leg for it? I would really prefer not to have to spend $300 on new Flowmaster Cats for it. Can't put a factory system back on without replacing the entire exhaust as whoever did the job cut out the rear bolt together section between the Cat assembly and muffler. I just put $1500 into it to replace the motor after spinning a rod bearing 500 miles from home, so the budget is a bit tight right now, but I really want the MIL off....

  2. #2
    Advanced Tuner Montecarlodrag's Avatar
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    Not possible without flashing a new calibration.
    Even if the commands to modify RAM's contents exist, the changes would be lost when the car is turned off.
    Unless you can find a PCM from a compatible vehicle from another country where catalytic converters weren't used, there is no other way than tuning,
    10 sec Montecarlo SS

  3. #3
    The only software/hardware to flash the 97 and 97 Vortec Black Box is TunerCat OBDII.

    Not only are you setting codes the fluctuating rear O2 sensors are messing with your fuel trims to 10%...

  4. #4
    Tuner in Training
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    Feb 2014
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    Quote Originally Posted by Rhys View Post
    Anyone know if there is a set of OBD-II commands that can be used to disable the rear O2 sensors and Catalyst Efficiency checks on the 96-97 "Black Box" PCM without using tuning software to rewrite the entire flash?

    I have a 96 K1500 Suburban I picked up that has had the Cats cut out already. Rear O2 sensors are still there and functional, but without the Cats, I get a constant on MIL and P0430 Catalyst Efficiency code.

    I would like to just disable the Cat efficiency checks, as I live in Indiana and don't have to worry about emissions testing. I have an ELM327 device, and I know I can use it to issue commands to the PCM. I know I can't use it to rewrite the flash, however, I have had very little luck finding any information on what sort of commands can be used. I don't really have any interest in spending $500+ on tuning software just to disable a DTC code, especially if I have to spend another $100+ on top of that plus a weekend of my time to do an LS1 (0411) PCM swap. I'm not looking to turn it into a performance vehicle, I only picked it up for towing a large camper, hauling scrap, and the occasional longer trip with the family.

    So, I'm hoping someone on here might be able to tell me if it's possible to disable specific DTC/MIL checks using only OBD-II commands, and if so, point me to the necessary commands to do so.

    Alternately, can anyone point me to a shop in the North Central Indiana area that has the ability to do this and won't charge an arm and a leg for it? I would really prefer not to have to spend $300 on new Flowmaster Cats for it. Can't put a factory system back on without replacing the entire exhaust as whoever did the job cut out the rear bolt together section between the Cat assembly and muffler. I just put $1500 into it to replace the motor after spinning a rod bearing 500 miles from home, so the budget is a bit tight right now, but I really want the MIL off....
    Move your rear 02s further down the pipe 2+ foot will cause the back o2s to swing like theres a cat present.