Can you help me with OBDII code: P0430 ?

[Eschrichtius]

Just an update, still no CEL code. Everything's working great and MPG is back where it supposed to be

 

[kingbilly68]

Bringing this thread back instead of starting a new one. My wife's 08 Yukon threw a check engine light yesterday. Scanned it and got a p0430 code. Is the O2 sensor still the place to start? Or should I plan on a cat? Thanks.


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[Beeker702]

I’ve been fighting P0430 for weeks now on my 2015 Tahoe . I’ve replaced both cats and all 4 oxygen sensors as well as all coils, plugs and wires. Cleared code and it comes back a couple of days later. Truck runs fine just have no clue why it won’t stay off for good. Had the fuels trims reset and that didn’t work

 

[swathdiver]

I’ve been fighting P0430 for weeks now on my 2015 Tahoe . I’ve replaced both cats and all 4 oxygen sensors as well as all coils, plugs and wires. Cleared code and it comes back a couple of days later. Truck runs fine just have no clue why it won’t stay off for good. Had the fuels trims reset and that didn’t work

There are several reasons for a P0430. The most obvious is a failed cat, even a new one. A large exhaust leak can set the code, such as a leaking exhaust manifold.

Aftermarket cats and O2 sensors don't play nice with the computer and they will set varying codes.

Finally, when the troubleshooting guide has been exhausted, it's usually time for a new ECM.

A new cat will often set a code within the break-in period, usually a hundred miles or so.

 

[Beeker702]

There are several reasons for a P0430. The most obvious is a failed cat, even a new one. A large exhaust leak can set the code, such as a leaking exhaust manifold.

Aftermarket cats and O2 sensors don't play nice with the computer and they will set varying codes.

Finally, when the troubleshooting guide has been exhausted, it's usually time for a new ECM.

A new cat will often set a code within the break-in period, usually a hundred miles or so.

I’m told by dealer that the o2 needs to be programmed after being replaced

 

[j91z28d1]

I’m told by dealer that the o2 needs to be programmed after being replaced

it's been talked about here. technically you could call it that. the o2 has a heater circuit in them and the ecm controls that with a pwm ground circuit. it needs what's called a heater reset.


but unlike normal module replacement that need progammed using gm's dealer software. when you clear the codes with a standard obd2 scanner it clears the heater data and the ecm goes thru a recal automatically.

the annoying part is the o2 itself. 99% of trucks will be fine with any old brand o2. but some seem to not work correctly with anything but oem. and not even ones made by denso, which is believed to be the oem manufacture of the gm part, but the actual gm part number o2. why, I don't pretend to know and tons of people can throw any old cheap auto parts store o2 in them and never give a 2nd thought. others it seems to be an issue.