P0430 cat replacement

The Gas and Diesel Engines - VQ40De, VK56DE, YD25DDTi, V9X, Transmission, Transfer Case, Oil, Differentials, Axles, Exhaust...

Moderator: volvite

nismopath
Posts: 136
Joined: Tue May 24, 2016 5:19 pm

P0430 cat replacement

Postby nismopath » Sat Apr 13, 2019 11:38 am

I have read up on this code and it seems everyone has to replace the cats. My question is that since I have the 430 code and not the 420 code, so I need to replace both cats or just one?
Either way, are they just bolt on cats? Can I knock that out in the garage with a wrench and sockets? Or is there more to it?


User avatar
smj999smj
Site Admin
Posts: 5708
Joined: Sun Jan 22, 2012 11:13 pm
Location: Prospect, VA

Postby smj999smj » Sun Apr 14, 2019 1:11 am

P0420 is the right bank and P0430 is the left bank, so, just one catalytic converter needs to be replaced (left side, upstream). It is a bolt-on part, but the manifold heat shield is in the way and trying to remove the shield often results in broken bolts. Most will trim away the part of the heat shield that is in the way. Removing the left-front wheel well liner gives access to the top side of the converter. The other issue is that the bolts/nuts can get rusty, so, a torch may be required to get some of them off. The main muffler assembly will need to be disconnected from the left and right, downstream converters. Then, the left bank, downstream converter can be removed so that there's room to remove the upstream converter from the bottom of the vehicle. You'll likely need some new hardware and you'll definitely need some gaskets. I would also recommend getting some new 10MM push clips to replace the ones on the wheel well liner that will likely break when you try to remove them.
Another option you can do to keep the light from triggering is install a CEL eliminator on the left bank, downstream oxygen sensor. This is essentially a long spacer that restricts some of the exhaust flow to the rear sensor and "tricks" the ECM. The run anywhere from $10 to $30, depending on what brand you get. I paid $12 for mine from Amazon and the CEL for the P0430 only came on once in two months, whereas it was triggering several times a day. I keep a $25 OBD II code reader in the glove box to turn the CEL out when it happens. If you have CA state type inspection, they will fail it if they see it. It's not an issue where I live.

nismopath
Posts: 136
Joined: Tue May 24, 2016 5:19 pm

Postby nismopath » Mon Apr 15, 2019 11:50 am

But if it is the o2 sensor, how will I know? Other than changing the cat and the code stays on. I don’t want to do one and it end up bring the other.

User avatar
smj999smj
Site Admin
Posts: 5708
Joined: Sun Jan 22, 2012 11:13 pm
Location: Prospect, VA

Postby smj999smj » Tue Apr 16, 2019 3:28 am

In my experience as a Nissan tech, generally if there is an oxygen sensor causing the catalyst codes, you will have both the catalyst and oxygen sensor codes stored in the ECM memory. The oxygen sensors can be monitored using a scan tool, but I've found that it's tough to get a good read on the front oxygen sensor, which is actually an air/fuel ratio sensor on R51's. It runs a much narrower band than "regular" oxygen sensors, like those that are used downstream. Catalytic converter seems to be pretty common on the 2005-and-up Nissan Pathfinders/V6 Frontiers and Xterras, especially from 2005-2007. If replacing a catalytic converter, you should know that most catalytic converter warranties require proof of replacement of the oxygen sensors at the time of the converter replacement (keep your receipts). Personally, at the very least I would replace the front sensor, as it is a primary input for the ECM to determine the air/fuel mixture, unlike the downstream sensor which is only for monitoring the post catalytic converter emissions.

nismopath
Posts: 136
Joined: Tue May 24, 2016 5:19 pm

Postby nismopath » Tue Apr 16, 2019 7:15 am

So if I have to get the upstream sensor anyway, should I replace that first.. see if that fixes the CEL ? Then if not, then replace the car?

User avatar
smj999smj
Site Admin
Posts: 5708
Joined: Sun Jan 22, 2012 11:13 pm
Location: Prospect, VA

Postby smj999smj » Tue Apr 16, 2019 10:00 pm

You can if you want to, but don't be surprised if it doesn't fix it.


Return to “R51 Engine, Driveline and Powertrain”