ok sounds good ill check out the ntk

 

If yours is not a federal emissions truck, you've got only two sensors. Crawl underneath and look.

Go with NTK (NGK), period.

Myself, when one sensor goes bad all of them get replaced. It's cheaper to just replace one, but it's less headache over time to shotgun the whole lot. Unless the difference is leaving your kids hungry or without Christmas, do them all at once and be done with them for another 100,000 miles or so.

 

Yes, P0420 OBD II universal definition is bank one. However, there is only one cat monitor on his truck.

To the OP-

Most likely it is a failed cat, as there are a host of other P-codes to indicate sensor-related problems (P0136-P0141). If you want to be sure, just back probe the signal wire on the cat monitor (downstream O2), and watch the voltage. It should hover around 300 mV and shouldn't fluctuate more than about 50 mV up or down. If it's switching like an upstram would, the cat is junk.

The guy at magnaflow is half right. While most of the time a cat failure is just a cat failure, often times on these rams, the oil from the plenum leak gums up the works in that honeycomb, and they stop burning the excess hydrocarbons.

 

he says he has 4 sensors - which would be true on a california emissions. since he lives in arizona, its possible that he's got that setup.


if you do have a 4 sensor system, bank 1 is drivers side. if you have a 2 sensor system, the only pair is named bank 1, but its located on the passenger side.

 

I somehow missed that. Ooops. But.....

Don't the California models use a four sensor system with two monitors for the single cat? I'm pretty sure they have one that installs in the cat itself, and then a true downstream. I could be mistaken, but I believe that on-the-cat sensor and an air injection system are the only differences for a California model exhaust; still a two-into-one cat set-up.

 

The Cali versions have two 'pre-cats' with O2 sensors on both sides. Then, a third, unmonitored cat further downstream. (this might vary by model year..... not sure on that.)

 

OK, I'll have to go with that, since I don't really remember. We don't see that many cali trucks here in Denver, and it's likely that the example I'm remembering could have been a pre-OBD-II or one that had an expensive cali system replaced with a cheaper Federal compliant one after failure outside of California. I don't believe I've ever seen a 2nd gen with pre-cats.

 

They don't make it to Michigan real often either.

 

Or if it was up here, a Cali truck would be sleeping in the shop now for the winter....

sprntpshr

 

i crawled under and looked and i doonly have two sensors, i also erased the code and drove it for a while and it hasnt come back on, so when i get some money together im going to replace both sensors, and when i get even more money i might get the magnaflow direct fit cat for i found for $165( found a coupon... its normally $206...thought that was a pretty good deal.