Automotive

Code P420 Catalyst System Efficiency - 2006 Nissan X-Trail

  • Last Updated:
  • Jun 6th, 2015 11:05 am
Tags:
None
Deal Expert
User avatar
Feb 9, 2003
19892 posts
4111 upvotes
9347934 downvotes
I got a similar code in my p/u that went away when I changed my spark plugs. If they're due to be replaced, start there. They're cheap and easy.
Deal Expert
User avatar
Feb 9, 2003
19892 posts
4111 upvotes
9347934 downvotes
billford wrote: The first quote is totally correct.

Exhaust flow will have negative pulses in between the positive pulses in a properly tuned exhaust system. In other words, it blows and sucks. You won't notice this at the tail pipe, but if you measure exhaust back pressure on a good engine, at various rpm's, you will see vacuum on the gauge. It can and will suck broken cat convertor particles back inside the engine. The closer the cats are to the manifolds, the worse the results.
No. Every negative pressure pulse is followed by a far greater positive pulse. This makes it impossible for a particle to travel from a cat all the way to a cylinder. A barely-measurable negative pressure pulse (if that's even the case) for a fraction of a second cannot suck anything several feet.
Deal Addict
Feb 6, 2011
2372 posts
3008 upvotes
i6s1 wrote: No. Every negative pressure pulse is followed by a far greater positive pulse. This makes it impossible for a particle to travel from a cat all the way to a cylinder. A barely-measurable negative pressure pulse (if that's even the case) for a fraction of a second cannot suck anything several feet.
Sorry, don't agree with you.

There's a writeup from Ford which analyzes failed engines. One cause is failed cat convertors or anything caught in a cat convertor from a failed engine. Cylinder scoring is the result. Precats can be inches away or even part of an exhaust manifold and can pull in debris easily.


Check out pages 13 and 14.
http://www.ifama.net/documents/engine_f ... alysis.pdf
Deal Expert
User avatar
Feb 9, 2003
19892 posts
4111 upvotes
9347934 downvotes
billford wrote: Sorry, don't agree with you.

There's a writeup from Ford which analyzes failed engines. One cause is failed cat convertors or anything caught in a cat convertor from a failed engine. Cylinder scoring is the result. Precats can be inches away or even part of an exhaust manifold and can pull in debris easily.


Check out pages 13 and 14.
http://www.ifama.net/documents/engine_f ... alysis.pdf
Or they can be physically above the manifold and gravity is the cause. Or a backfire. Or poor repair procedure. Or a rollover accident.
Deal Addict
Feb 6, 2011
2372 posts
3008 upvotes
i6s1 wrote: Or they can be physically above the manifold and gravity is the cause. Or a backfire. Or poor repair procedure. Or a rollover accident.
I admit that I have not seen every Ford vehicle made but I'm not aware of anything current with the cat convertor above the heads. Which one has this setup? Please reply with pictures if you have any...If not, a year and model...very interesting setup having the cat converters above the manifold...

The only thing I can think of is the diesel trucks with the exhaust stacks on the side of the cab, but those are not cat convertors...
Deal Guru
User avatar
Jun 28, 2003
12183 posts
5650 upvotes
Ottawa
Just a quick update for my situation, guys: I brought the car to my mechanic last week and it was indeed code P0420 again. He told me since I don't have to do e-test for another year and a half, I should just *ride it out* until then instead of spending a significant amount of $ to fix the problem right now (He gave me a quote of $600+)

I am obviously not too comfortable with that suggestion so I decided to get a second opinion from another mechanic who actually more or less say the same thing. The kicker is this guy would be charging me at least $1K+ for the job because there is no after-market part and he will have to get 1 from the dealer which will cost an arm and a leg.

I certainly don't want to spend anywhere more than $1K on this (the car is probably worth $4K, if at that, at this point). A local Nissan dealer quoted $2K for the part (the whole manifold, has to order from Vancouver) and $350 for labour so fudggetaboutit.

Btw, the light has gone away since yesterday, fingers crossed...I did order a code reader for future use...I think my best course of action is to get the cat converter for about $200 from Toronto or the U.S. and bring it for my mechanic to replace. The car is still running fine, knock on wood but I definitely would like to get this done sooner rather than later.
Sr. Member
User avatar
Jul 12, 2005
697 posts
8 upvotes
I have a 2006 xtrail LE.
I had an oil pump seize at 117,000km which caused my engine to run dry and a piston blew through it..
luckily had the factory extended warranty.. new engine was put in and it has @40k on it.. had the differential replaced last year.. truck is in very good mechanical state but the cos.etic state a few bumps on back bumper and I hit ran into someone at low speed which messed up.my front bumper..
I have had it for 10 years and decided to trade it in.. but if your looking for a cheap parts car.. I may have one for you
Deal Guru
User avatar
Jun 28, 2003
12183 posts
5650 upvotes
Ottawa
The light has stayed off solidly for about a week so I decided to take my chance and do an e-test (turned out mine is due this year) and guess what it PASSED!

That will buy us another 2 years...we are still going to see another car later on this afternoon but this will give us some leverage in terms of negotiations ;)

Top

Thread Information

There are currently 2 users viewing this thread. (0 members and 2 guests)