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Yeah, you are probably screwed.
Could be the Cat, Nissan uses lousy ones.

But it is still more than likely an oxygen sensor.


Cats and O2 sensors are covered for 80K.


Homer
 

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I've never heard of cat problems on Nissans. On some 4-cyl Altimas, the precat in the exhaust manifold had issues, but that was only with that one engine, not with the V6.
 

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I got the P0420 code Catalyst system efficiency below threshold error at 134000 miles.

For anyone looking for a replacement, Code 420 indicates that its bank 1, which is the Right Hand side of the engine when standing on the drivers side looking towards the passenger side of the engine bay. For most people minds, this translates the the rear of the engine.

I'm replacing mine with an aftermarket cat from eastern. The best deal I could fine was for $263.73, sure beats the $750+ the stealer wanted to charge. You still have to get your own gaskets since they don't come with the replacement catalytic converter. Of course I'll install a new O2 sensor with it as well.

I found the price at http://www.import-catalytic-converter-warehouse.com


I also had a code P0327, which indicates the knock sensor voltage was low. I found the root cause was a short in the knock-sensor sub-harness that extends about the last 14" to the knock sensor. The replacement harness is $54 cost, but because I need it quickly, I paid the dealer price of $105. When I took the harness apart the wire is a coaxial style cable to shield the signal from spark plug coils. The cable has its outer shielding cut back and attached to a 2nd wire for the harness connector on both ends. When this was done the center wire jacket was nicked and over time had pulled back from the heat, exposing the center wire to the ground shielding - creating the short. The wire harness looks like it was made in a basement.

Since I have the intake manifold off, I decided to pull all the plugs and do a compression check. The low end was 192 PSI and the high side was 200 PSI with average about 195 PSI. Standard compression is 185 PSI. This is outstanding on an engine with 138,000 miles. The compression reading tells me that the valves are all seating properly and the piston rings are good.
BTW... this is the same engine the dealer told me I needed to replace.
 

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WrenchGremlin said:
I got the P0420 code Catalyst system efficiency below threshold error at 134000 miles.

For anyone looking for a replacement, Code 420 indicates that its bank 1, which is the Right Hand side of the engine when standing on the drivers side looking towards the passenger side of the engine bay. For most people minds, this translates the the rear of the engine.

I'm replacing mine with an aftermarket cat from eastern. The best deal I could fine was for $263.73, sure beats the $750+ the stealer wanted to charge. You still have to get your own gaskets since they don't come with the replacement catalytic converter. Of course I'll install a new O2 sensor with it as well.

I found the price at http://www.import-catalytic-converter-warehouse.com


I also had a code P0327, which indicates the knock sensor voltage was low. I found the root cause was a short in the knock-sensor sub-harness that extends about the last 14" to the knock sensor. The replacement harness is $54 cost, but because I need it quickly, I paid the dealer price of $105. When I took the harness apart the wire is a coaxial style cable to shield the signal from spark plug coils. The cable has its outer shielding cut back and attached to a 2nd wire for the harness connector on both ends. When this was done the center wire jacket was nicked and over time had pulled back from the heat, exposing the center wire to the ground shielding - creating the short. The wire harness looks like it was made in a basement.

Since I have the intake manifold off, I decided to pull all the plugs and do a compression check. The low end was 192 PSI and the high side was 200 PSI with average about 195 PSI. Standard compression is 185 PSI. This is outstanding on an engine with 138,000 miles. The compression reading tells me that the valves are all seating properly and the piston rings are good.
BTW... this is the same engine the dealer told me I needed to replace.
That is a fantastic report you just wrote up. A pleasure to read.
 

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Eric wrote:That is a fantastic report you just wrote up. A pleasure to read.
Thanks Eric.

I think the reason the catalytic converter expired was that I waited a bit long (117K instead of 105K)to change the spark plugs and the gap became just to great to jump. The evidence was there as the plug was wet when I removed it. This in effect dumps raw fuel into the cat causing it to burn very hot and ulitmatly clogging it up. The driving effects are the same as fuel starvation. The car will hesitate and surge, you may even hear rattling when letting off the gas.
 

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WrenchGremlin said:


Thanks Eric.

I think the reason the catalytic converter expired was that I waited a bit long (117K instead of 105K)to change the spark plugs and the gap became just to great to jump. The evidence was there as the plug was wet when I removed it. This in effect dumps raw fuel into the cat causing it to burn very hot and ulitmatly clogging it up. The driving effects are the same as fuel starvation. The car will hesitate and surge, you may even hear rattling when letting off the gas.
That is an interesting point. I find it annoying one has to remove the intake manifold to change the plugs but if thats what it takes, I'd rather do that than be forced to buy a new cat.
 

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I appreciate the posts. I'm not much of a blogger but I have seen some useful info here. I changed my spark plugs with the info I received here.
I didn't change them at "105,000" miles as "recommended" but it wasn't long after. They weren't dripping as another post stated. But, I had some of the symptoms. What amazes me is the complexity of an engine (removing the cowling, 22,000 vacuum tubes, wiring, etc.) Hell the air intake has a line running from the radiator to cool the air!
Anyway, thanks for all of your info. Some of you are bigger gearheads than I am. I don't want to turn my Murano into a supercharged, 350Z on steroids; but I appreciate all of your efforts. I just want it to perform at a reasonable cost (considering what I paid for it).
 

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Ok, got my engine back together with the new wiring sub-harness for the knock-sensor. Most of the HP has returned and its much more responsive than its been in months. No more code P0327 for me! The last thing is to replace the catalytic converter to get rid of code P0420.

Side note: I have an '03 MO, the connector on one end of the new knock sensor sub-harness was molded as a mirror image to the harness that it was replacing and since the connector is keyed, this makes it impossible to put on the connector without modifications to the connector on the main wiring harness. Not wanting to cut off the keys on the connector that resides on the main harness, I examined the new connector and figure out that I probably could release the electrical pins and swap the connector with the one from the old harness. This was accomplished by carefully removing the plastic key and gently pulling back the plastic arms that hold the wire pin in place. This took about 45 minutes because I had to make the tools to do this without causing damage to the part. This all makes me wonder about the group designing parts at Nissan, why mirror the part?
 

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UPDATE - When is enough... enough?

I'm now at 160,000+ miles; the SES light is still on and now the right rear exhaust manifold and the struts need to be replaced [about $1000 at my local Nissan repair shop, not a dealer].

Over the last two years I've sunk over $5000 into my Murano for repairs. I drive the Mo close to 50,000 miles a year for my sales job.

When is enough, enough?

I took it around to a few dealers and it looks like my high mileage Mo is only going to bring $5000 to $6000 as a trade in [I'm looking at the 2009 Subaru Forester XT].

I'd spend the $1000 to repair the manifold and struts if I thought that would get me another 40 or 50,000 miles [one more year of use]. I just don't trust that there won't be another $1000 fix in a month.

What would you guys do???
 

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The struts is a safety issue and needs to be taken care of. As for the exhaust manifold, I assume there is a clogged catalyst in there or a bad O2 sensor. Both will affect gas mileage (esp since you drive 50,000 miles a year) so it may pay to get it fixed. You won't pass emissions for registration if the SES light is on.
 

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Eric L. said:
The struts is a safety issue and needs to be taken care of. As for the exhaust manifold, I assume there is a clogged catalyst in there or a bad O2 sensor. Both will affect gas mileage (esp since you drive 50,000 miles a year) so it may pay to get it fixed. You won't pass emissions for registration if the SES light is on.
That's funny you should mention that... just last month my plates expired. I was able to pass the emissions inspection but only because my Nissan guy was able to work some magic and reset the SES light long enough to pass the test.

I agree about the struts... it feels like I'm driving a ghetto hoopty.

The manifold is cracked and is making all sorts of noise and releasing a strong exhaust smell. Is it bad that I'm getting used to the smell. My wife drove the Mo for the first time in a long time last weekend. She was mad at me for not getting it into the shop sooner.

 

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Re: UPDATE - When is enough... enough?

FlyerNo9 said:
I'm now at 160,000+ miles; the SES light is still on and now the right rear exhaust manifold and the struts need to be replaced [about $1000 at my local Nissan repair shop, not a dealer].
$1K doesn't sound bad at all for struts AND an exhaust manifold. The dealer would probably get twice that. Also, needing those at 160K miles isn't bad either.

As for what the car will need next, that's anyone's guess. But 50K miles a year is a lot on ANY car. Compared to making a down payment and then monthly payments on a new car (and then figuring in the depreciation), usually doing periodic repairs - especially on a Japanese made car - is a bargain.
 

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SES P0507 code?

according to this error from auto zone it has a large vaccum leak. i currenty had 3 part fuel system clean at valvoline shop ever since then the error show up and found out that they did place my air intake improper so i fix it myself and had the code reset by them and it came back but only for about 7 days and it when away for 1 day. it came back and hasn't left since. i try to reset the code myself with the instruction Tyler_Canada on this thread give but no luck. i dont know exactly what am doing not that technico with cars by not afraid to try to do it myself with the correct instruction. i fix the front bump myself (dad dent the front about the size of my head) and passenger window motor with no instruction but paid close attention to detail. LOL. do i need to reset the code again and try to get the car to relearn air intake for the throttle body.
if So any complete instruction would be great. Thx
I have a Nissan Murano 2003 SL AWD fully loaded (just missing nav system) with 120,300 miles on it now.
 

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Hey Friends.
There has been the occasional problem where even when the cap is tight the code is triggered. One person had the dealer "reduce the sensitivity" so that the problem wouldn't keep reccurring. You might want to check into this if you know the cap is being tightened properly. Note that the cap should be "clicked" at least once to reduce this problem.
 
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