P0430 ?

[2kHOEz71]

Hello all, any experience with the code p0430? 2000 Tahoe z71 obs with 195k runs perfectly normal but today while driving a couple miles engine light came on scanned and got p0430? Anyone have experience with this code please comment thank you.

 

[Schurkey]

P0430 Catalyst System Efficiency Below Threshold (Bank 2)

Read more at: https://www.obd-codes.com/p0430
Copyright OBD-Codes.com

The service manual has a complete diagnostic chart for assessing this code. Fairly likely the catalyst is worn-out, but it could be a faulty sensor or a rich/lean problem in the engine. Could even be a wire-harness problem.

Follow the service manual procedure, find out what's wrong. When it was my Trailblazer, I needed an O2 sensor and a new catalyst.

 

[2kHOEz71]

Thx for the reply

 

[Nad_Yvalhosert]

Your Tahoe, my 2000 Yukon Denali, like all the 96-98 pickup trucks, '99 SUV's (technically the 5.0 & 5.7 were used till 02 in the vans) those half ton vortec engines suffer from an exhaust flange that warps, blows out the gasket and set a bank 2 downstream O2 sensor code. That's because the downstream O2 sensor is mounted AFTER that friggen flange

Check the flange for an exhaust leak before replacing any parts. If it is indeed blown out and warped, replace the gasket. If it doesnt seal, and blows out again, theres a company called REMFLEX. Their gasket material will crush, conform to the uneven metal, and rebound to seal when its heated for the first time.

I tried to sand it smooth, double gasket, high heat muffler cement, you name it, to get it to seal. Wasnt until my fat fingers typed away on the ole internets and found REMFLEX. And I'll reccomended it to anyone that needs it.

 

[Schurkey]

Thanks for the reminder. My Trailblazer needed an O2 sensor, a catalyst, AND an exhaust manifold donut seal, the original was blown-out and burnt-up.

 

[b454rat]

Weird, my tahoe came up with that code yesterday. i have 4 new O2 sensors, a new cat less down pipe, and no exhaust leaks ( I hate leaks) but yet get the code. I only got it once, so maybe a fluke, but we'll see. i use red hi heat formagasket on all exhaust gaskets. I put a semi thin layer on both sides of the gasket, so far it's worked great, even on cheap gaskets. My yukon has the same down pipes, and get no codes.

 

[Schurkey]

Weird, my tahoe came up with that code yesterday. i have 4 new O2 sensors, a new cat less down pipe,

Is that "a new cat, less down-pipe"? Or "a new cat-less down pipe"?

If you don't have a catalyst, of course you're going to get "catalyst efficiency" error codes. the upstream and downstream O2 sensors wouldn't be reading the change in O2 that should be caused by the converter (that isn't there.)

 

[b454rat]

no cats at all. But why would one vehicle not have any lights come on at all, and the other whenever? When I got the tahoe the one cat was cut off, and the other was gutted, so really don't see a difference, and the light wasn't on for catalyst. It could be the pigtail, since the original was corroded, maybe it doesn't like it or something.

 

[JayMB]

My friend has an '01 S10 4.3 V6 (basically the 6-cylinder version of the 350 Vortec). He has no cats and it has never thrown a check engine over it. I have no idea why. Maybe the sensor is just that dirty. They make a plug-in thing that plugs into the rear O2 sensor plug on the harness and sends the PCM a signal consistent with a healthy cat. Used to see them on ebay for like $10. Grab two of those if you don't want the CEL on.