I have a 05 altima which has its service engine light on and the code when tested was a p0420. When I asked two different mechanics what to do with this they gave me different answers. One was sure my cat...
Sigh.If you DONT know what it is, you really should take it to someone who does and TRUST THEM. if you dont know who to trust, then you really need to ask around and find someone.
NOW, P0420 on a 2005 is USUALLY always the cat. However other things can make a cat set the code when it still may have lyfe left.
O2 sensors need to be in GOOD condition (not just barely passing OBD2 test).
Zero, none, no, absolutely NO EXHAUST LEAKS! Any exhaust leak between the engine and the catalytic converter can cause a good converter to fail its testing because the excess Oxygen from the leak currupts the lightoff. And Exhaust leaks near an Oxygen sensor can cause the computer to make mistaken adjustments to fuel mixture, which creates a rich or lean exhaust, which then causes cat not to work. I repeat for the cheap seats: NO EXHAUST LEAKS!!
Now, yours is a 2005, so check for factory service bulletins (dealer or autozone) regarding cat defects or recalls. If you dont find any, AND the above proves out, AND there isnt any red herrings...you probably need a cat. After 2002, the computer in that car is pretty smart...it knows to test its O2 sensor, its warmup tyme, and it compensates for alot of subtle variables. If there are no OTHER codes but the 420, the computer probably is right and you should trust it (post 2000 anyway and assuming still the exhaust leak thing is tested OK)
An expert could test this for you BTW and youd know for sure. Guessing is bad and costs money sometymes that is excessive and un-needed. You dont rewire your TV or DVD players innards when they dont work, and they cost a couple of hundred. Now you wanna fix something that sold new for 10-50k or more, with over 3000 moving parts, that is safety related, heats to over 400 degrees surface and 250 water, was designed by no less than 35 engineers with degrees...using a post on the web from people you dont know?
hey, more power to ya. Just be ready for the web solutions to sometymes be wrong or confuse even more.
Aug 24, 2011 |
2005 Nissan Altima