Hi, I'm new to this group and I have a question. I keep getting the P0430 code. My IS350 has 177000 miles on her. The code will come on on as low as 11 miles, most of the time it's well over 100 miles and as high as 290 miles. My question is would the O2 sensor the posable cause? No problem with power output and she will pull over 30 mpg on the highway. Any ideas?
Krash

 

Probable the O2 sensor, you could switch it places with the other one, I believe your engine has 3 or 4, and see if the code changes to the new position. But at 177k, your car will run better and more efficiently with a full set of new O2 sensors. They get lazy as they get old, and don’t fine tune the engine nearly as well as a new set would perform. They aren’t particularly expensive or difficult to install. And probably pay for themselves in less than a year.

 

The oxygen sensor is a possible cause, but the most likely one is an exhaust leak. Often due to corrosion near the Y-pipe. Exhaust leak causes catalyst to take longer to light off than it should, and it starts to sporadically fail the efficiency test that runs about 10 minutes after a cold start.I would definitely check that first.

 

Any thoughts on stock or aftermarket sensors? Each stock sensor is $160. Yikes. That being said, its worth it if the fuel mixture is correct and does not foul the catalytic converters.

 

Depends on which one you're replacing.
Upstream, or Downstream.

Rockauto.com should have the Denso for both. You also can add a 5% discount at checkout if you have a valid recent code. Search online to find the latest code for this year, and month.

 

Don't forget about ebay and Amazon too! New Rear Oxygen Sensor 89465-30730 for $37.59

 

Maybe... Lots of people on this forum have been burned by fake Denso spark plugs, and a little Googling shows that counterfeit Denso O2 sensors are a thing too. Caveat emptor.

 

Please don't fall for these cheap replacement parts. Purchase genuine Denso parts to guarantee perfect performance. I remember when I was installing my PPE headers. I went ahead and order 4 new O2 sensors and installed everything at once. I saved a load by purchasing on eBay and Amazon.

 

You'll want to stick with ones that are direct replacement and not the generic ones that requires u to attach the old plug to the new sensor, they can be hit and miss. Seems like Bosch makes an excellent O2 sensors