# 2005 2.5L Altima - Dreaded P0420



## LeftOfSanity (Jul 13, 2011)

Greetings all,

Just found these forums and have been doing some research. I have seen there are issues with the pre-cats melting and damaging the cylinders. I have also found it could be just getting ECM re-programmed, or the O2 sensors. Also about the engine eating oil.


I saw most of the issues were on 2002, are they all valid for the 2005 also?

I started getting the CEL and had it pulled, it was P0420. I think I might have the oil issue also. I have to keep my eye on it.

I got this car from a buy here/pay here place, still paying on it. Out of warranty, drive it about 100+ miles a day (50 mile commute each way).


Any input helps.


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## LeftOfSanity (Jul 13, 2011)

I cleared the SES/CEL light by unhooking the battery for 20+ minutes, have driven 65 miles so far, hasnt come back on yet. 

::crossing fingers::


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## LeftOfSanity (Jul 13, 2011)

Well, I forgot about the sensor seeing the fault on the second trip, so it did come back on.

Does the 2005 model suffer from the melting pre-cats? I would think they would have fixed it by then.

Anyone know?


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## LeftOfSanity (Jul 13, 2011)

Well found out today the car was already serviced for the ECM reprogram issue. 

Im going to test the O2 sensors tomorrow, if they check out, I guess I replace the exhaust manifold/cat. 

Cheapest direct fit I found was $279.


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## smj999smj (Jan 1, 2006)

If your engine is already burning oil, it's a temporary fix for the light until the oil contaminates the new catayst media and ruins it. If you are burning oil, there's a good chance you need an engine AND a catalytic converter.


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## LeftOfSanity (Jul 13, 2011)

smj999smj said:


> If your engine is already burning oil, it's a temporary fix for the light until the oil contaminates the new catayst media and ruins it. If you are burning oil, there's a good chance you need an engine AND a catalytic converter.


I havent verified that yet.


I see in the 2005 Altima Warranty booklet for California Emission Performance\Defect\Long Term Defect

"** Sentra with 1.8 engine and California Emission Altima with 2.5 engine ONLY: Warranty coverage is 15 years/150,000 miles, whichever occurs first."

I found this Service Bulletin NTB09-046 located here:

http://ww2.justanswer.com/uploads/baddad1/2010-08-07_133622_NTB09-046.pdf


According to the servcie bulletin it needs cat replaced and ECM reprogrammed.

I have 144k miles would I be covered if mine is a Cali emissions car?


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## Biscuit (Mar 5, 2005)

I just fixed this problem on my gf's sisters 05 Altima with 130k miles. I gutted the cat (in SC so no inspection) using the writeups found on google and I had GREAT success. It was throwing the code and going into this mode where it just wouldn't go. After the procedure, power was restored and no more CEL.


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