P0430 code and coolant temp sensor

[TexasPPV]

Seems like a common issue here.

P0430 code low efficiency cat bank 2.
Also, sometimes the coolant temp sensor gets “stuck” and the fan runs full blast. I would say this sensor gets stuck 1/20 times on startup, but when it does it’ll do it a few times in a row.

I have seen that sometimes a faulty coolant sensor can cause this code.

I am replacing the coolant housing/sensor this Saturday. Hoping this will fix the issue.

If this does not work- what’s next? Go ahead and replace all 4 oxygen sensors? New cat? Check for exhaust leak? I’ve even seen people say broken bolts on the exhaust can cause this code.

I know my way around a toolbox and electrical systems, but my knowledge on drivetrain and efficiently systems is limited to what I have read on this form.

Thank you in advance for your time and help, I hope this finds you well.

 

[TexasPPV]

Edit: 191,000 miles. Bought it at 172,000 from the state of Texas. Previously was a state trooper car.

Runs great, occasionally get vibrations on idle at a stoplight.

 

[swathdiver]

A P0430 is almost always a bad cat unless there is a large exhaust leak on that side or the O2 sensor itself has not been tightened all the way. Very rarely is it anything else but stranger things have happened.