Catalytic converter and oxygen sensor questions and more...

[FrankA6]

We have a 2005 Nissan Murano SL with about 117k miles on it (got it brand new) and I recently got the P0420 code , the car has a lot of power loss and hesitation when accelerating and is also making a rattle/metallic sound for a few months now. I just got back from my indy shop that works on our Audi's and he narrowed it down the the back catalytic converter , when you hit it or move it, it has a lot of rattling, this is the piece I'm talking about.



Now, I wanted to change the 2 O2 sensors that are near that piece while we are under there, are they the upstream or downstream sensors or either or?



And lastly, I know all about the throttle body problems and CVT problems and I'm pretty sure the lack of power and acceleration problem could be this bad catalytic converter but if its not is there anyway to have Nissan replace the CVT transmission? I noticed they extended the warranty to 10 years or 120k miles , the car is almost near 120k miles, should I just take it in and have them look at the CVT and how will I know they wont just lie and tell me its fine?

As far as I can tell the car shifts fine and the trans works fine...


Thanks a bunch guys!!!

[lgt]

OBDII uses an pre cat O2 sensor used to calculate short term and long term fule trims. There is also a post cat O2 sensor used to monitor the efficency of the cat converter. I'd make sure you need them though. They are about $100 a piece.

[njjoe]

Originally Posted by FrankA6

Now, I wanted to change the 2 O2 sensors that are near that piece while we are under there, are they the upstream or downstream sensors or either or?

[FrankA6]

So there is only 2, thanks!

Where do you guys buy most of your parts?

[njjoe]

Originally Posted by FrankA6

So there is only 2, thanks!

Where do you guys buy most of your parts?

Actually, there are 4, not 2, O2 sensors on the exhaust system. The schematic lists the first set of sensors as Air/Fuel (A/F) sensors. They are actually O2 sensors.

-njjoe

[FrankA6]

Do you have part numbers for the 2 lower ones?

[nitely]

Nissan calls it A/F sensors but some vendors will call it O2 sensors...what matters is the location of the sensors. The one before the CAT is the sensor that affects the performance of your engine. The one after the CAT only tells you if the CAT is dead or getting there. Rattling can be caused by loose or rusted exhaust pipe brackets. Since you are out of warranty mileage wise on your CAT it is possible that its gone. But you need to know which one or both. The 3rd one does not fail as fast as the first two. You will usually end up replacing the sensor after the CAT if the CAT is dead.

Check here for part number. http://www.nissanpartszone.com/code/...-parts-61.html

[baseball4life]

Frank,

I got a SES last month (on my 2006 Murano with less than 55,000) took it to Nissan dealership they came back with Code P0420. Nissan North America covered replacing the Catalytic converter/gasket-exhaust.
I had O2 fuel sensor replaced last July. I've since read that 02 sensor most likely was leading cause for the CC to go out.
I'm beginning to suspect Nissan keeps the Murano on the road becasue they make more money on parts & labor than the sale of the car.