P0430 Troubleshooting

I am working my way through this (hopefully). I did a few basic things... ensured that there was no corrosion on the battery terminals, installed a new air filter, electronics cleaner on the MAF...

I reset the light once and it stayed off for two weeks. It is back on, and today I pulled the rear O2 sensor. I want to make sure I am checking it correctly per the maintenance manual. If I am doing it correctly [see image with terminals marked, below] I am getting 15.8 ohms between terminal 1 and 2. I am reading 0 ohms between terminal 1 and 4, leading me to believe it is bad.

Just want to confirm I am reading the MM content correctly (i.e. I checked the right terminals). Also, should I pull the upstream sensor and check as well, or replace this one first and see if the CEL light goes out?

The more I read, the more it sounds like a bad CAT problem though...

 

IAW the manual as you stated the sensor is defective pin 1 to pin 4 should not read zero ohms it should read 10,000 ohms or higher on pin 1 to pin 4.

 

Pin 1 and 4 on the new sensor read 0 just like the old one ?? Pin 1 to 2 reads 16.

 

usually its the O2 sensor, not the cat. Im not saying cats dont go bad, just typically its not the first thing to go bad.

 

The manual must be wrong.

 

2006 trd sport, cc v6 auto. 250000km


Having the same trouble, but trying to get a
little more info before pulling out the old credit card.
Here are screen shots from my obd2 scanner. Does any of this info help diagnose a bad 02 sensor?
It's a nice tool, just haven't figured out everything about it yet.

 

Rarely is a P0430 a 02 problem, the sensors are working and thus verifying the cat has failed.

The downstream O2 starts to swing fast up and down with the upstream and triggers the code. If the sensors were bad they would be slow or not reading at all, this would be the opposite of a P0420/430.

Measuring resistance in the automotive field is a greasy beast, it can mislead and cause a lot of wasted money on sensors of all variety's.

You need a bank 2 cat.

 

As they say around these parts. Merci beaucoup.

 

Any progress? I just got this code

 

Replace the cat. Don't buy a cheap one either.

 

I suppose I should correct and say I'm getting the P0420....but mine is a 4 cylinder. Regardless its the same signal to the computer. I'm going to have to try and go with the Exhaust leak path first....followed by a bench test of the O2 sensor, and I'm thinking of investing in a thermometer gun...but I'm not sure it will be necessary.

Mine is a 2006...so a 12 year old truck with a 152k miles on it...well, I suppose its about time for some exhaust work.