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  1. #1

    Exclamation check engine light code p0430

    Well this just happened about 2 hours ago well driving. My book says its p0430 three way catalytic converter system low efficiency (bank 2).
    What in the world does that really mean.

    Information for the truck:
    1996 chevy Tahoe LT with 5.7l vortec and 4l60e tranny.
    197,280 miles. Bone stock engine ran only highway miles until I got it at 193,500 miles since then mainly city miles. Recently the truck has been running rough, has poor acceleration/power and sounds like it it missing. Soon I'm replacing the plugs, wires, distributer cap, and fuel filter. Recently the truck had its rear main seal and oil pan gasket replaced. Currently running conventional oil :( with a Fram tough guard filter. Truck sat with no oil for almost three weeks well I was working on it then I had to have it towed to a shop who finished the work.

    This truck is my baby and I want it back to how it was when I bought it.

    1996 Chevy Tahoe LT 5.7L V8 4X4 205,000+ miles. Built proudly at Janesville Assembly in Janesville, Wisconsin
    Basic mods: Lights all over, bunch of electrical work, and a couple cooling mods.

    Check out my other mods in My Garage:

  2. #2


    Are you still getting the noise from the passenger side on accel? Bank 2 is the passenger side I believe. With it running rough, I wonder if something is going on with the passengerside cylinders. Stuck valve? Broken valve spring? Collapsed lifter? If I let my 1995 silverado sit for a few weeks it would run like crap for a few miles. A valve was sticking or a lifter was not working. But after it warmed up it would run fine. any way, I found this on another site:
    A code P0430 may mean that one or more of the following has happened:

    • The catalytic converter is no longer functioning properly
    • An oxygen sensor is not reading (functioning) properly
    • There is an exhaust leak

    First, inspect for exhaust leaks.
    Next step is to measure the voltage at the oxygen sensor on Bank 2.

    I would check the voltage of the 02 sensors. But, I would not start throwing new o2 sensors and a cat at it until I figured out why it is running poorly. The miss you have and rough running could actually be causing it to not be burning exhaust correctly, hence your code. Just my $.02. If you get a chance to look at the sensor right after the cat on the right side find the number on it and PM me with it, I may have one in "stock" that I can send you for the cost of shipping. Or look it up on amazon or a place of your choice. I need the AC number should be a number like AFS 72.

    1995 Silverado 4x4
    6" BDS Suspension Lift-3" Body Lift-Add A Leaf in rear -Trailmaster SSV Shocks-Duel Steering Stabilizer Kit -AirAid Cold air intake-
    4.56 Gears with Detroit Auburn Locker-Pro-Comp Traction Bars with duel shocks-Aluminum Skid Plate Kit-38.5" x 16.5" Mickey Thompson Baja Claws-Constant Dropping fuel gauge

    2005 Yukon XL Jet Power Programmer, Bilstein Shocks, Bilstein rear springs, Helwig Anti-sway bars, EGR Window Visors, EGR Hood Shield, Denali Headlights, Headlight harness upgrade, GE NightHawk Bulbs, White Night Rear lighting system, Russell Braided SS brake lines, PowerStop Brake pads, PowerStop cross drilled and Slotted Rotors,
    2002 Silverado ext cab 2wd (Sold)
    2003 Yukon XL (Totaled)

  3. #3


    What's funny is I'm fairly sure that's the o2 sensor I just replaced. And yes the noise is coming from the pass side.

    1996 Chevy Tahoe LT 5.7L V8 4X4 205,000+ miles. Built proudly at Janesville Assembly in Janesville, Wisconsin
    Basic mods: Lights all over, bunch of electrical work, and a couple cooling mods.

    Check out my other mods in My Garage:

  4. #4


    I would get that code looked at in more detail. It should be capable of doing that to better determine if its the Cat or O2 sensor. Not unheard of for even new O2's to go bad. When they do, the computer has to compensate because it's about Emissions thanks to our wonderfull Govt Regs. No need to replace sensors and it's a Cat or vice-versa. Spend a few bucks and get the full code breakdown before acting.
    '13 Silverado 2500 | Crew Cab 2WD W/T | Vortec 6.0 | Diablew Tune |
    (Various Chrome items & Bestop Tonneau...)

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