Had my trusty Heep throw this code for me over the weekend. Finally got it scanned and came back with:

P0432 - Main Catalyst Efficiency Below Threshold (Bank 2). From what I've gleaned so far is that I've got 4 O2 sensors, 2 pre and 2 post mini-cats across 2 banks.

Is it worth throwing money at all 4 O2 sensors before tearing into and replacing the cats? Engine's been running fine, doesn't seem to bog down or struggle at idle and it starts right up.

 

I went through this awhile back in my '00 CA Emissions. So it could anything from the O2 sensor(s), to an exhaust leak, to fuel trims, and probably one or two things I am forgetting. People will tell you that 95% of the time it is the cat. In my case that is what it turned out to be. I went with a Walker. 52304. This is the one for CA Emissions vehicles not registered in CA or NY. If you do determine it is the cat and are going to replace it you might want to consider buying new hardware for where it connects to the exhaust manifolds. Not cheap but not outrageous but it would suck to not have them on hand if you happen to need them. Part #'s are:

6505754AA
6506546AA

You will need 4 of each.

 

Thanks Ralph! I stumbled across a few of your posts in similar threads. Went ahead and jumped on some new NTK/NGK sensors to get the ball rolling as they were low on stock.

I'm in OK so I think I can opt for the cheaper Walker precats that are just non-CARB. It's funny that the pre-cat pipe is nearly the same cost as 4 new sensors

I'm guessing at ~150K they sensors are the factory versions and could use change-out if I'm digging around down there anyway. Guess I'll start with the O2 sensors and move to the pipes if the code shows back up.

Code showed up as a pulled into a parking lot and stopped so beats me. Ran fine on the highway all the way up, all the way back and this morning I put about 45 highway miles on it with no issues.

Thanks for the tips.

 

You have a CA Emissions Vehicle. The cat part # I gave is not a CA cat. The Walker CA verison of that cat is almost twice as much. But does come with a better warranty though. Now I have idea what the Emissions laws in your state are. Or even if you have emissions.

 

Right, I was just confirming that I can go with the P/N you gave me. Oklahoma doesn't have any emissions controls that would effect me. I think RockAuto has that Walker p/n for ~180$.

 

I am sending you a PM.