# 2003 Altima 2.5S help plz!



## amistry (May 30, 2011)

I have 03 altima 2.5s with 97K miles. 2 weeks ago I had a check engine light came on and random total shut down of the car at intersections/stop lights. Also after driving for ~15 min it started vibrating like crazy. Code reader showed P0303 (cylinder 3 misfire) and changed spark plugs. Still same problem and took it to Firestone. Guy kept diagnosing for ~2 hrs and said you have to replace ignition coils and started pointing out random stuff like your radiator is bad but I said I will fix it later. Ended up paying ~$800. I know its a lot and I could have replaced coils myself but I called Autozone and they said they can't accept return unless part is defective. Firestone said he will take it if this does not solve the problem. Drove ~100 miles and light came back again. This time it shows 2 codes *P0420* (catalytic converter system - efficiency below threshold) & *P0335* (crackshaft position sensor - circuit malfunction).

I am not a too much of a mechanic but do you guys have any suggestions?
Ignition coils should never have been changed? Anyway I can fix it myself or how much shall I expect to spend?

how do you guys find a trustworthy mechanic? I have been to dealers to B&M stores but I have never been satisfied with any of them. They all seem to find random problems/suggestions and try to charge you $$$ even if you just went for oil change!

Thanks!


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## rogoman (Dec 16, 2004)

You could have an intermittent coil pack in cylinder #3. Swap it with cylinder #1, then with your code reader, clear out all fault codes. If the original P0303 code now shows P0301, then you've got a bad coil pack.

For the P0335 code, the sensor itself may be bad or the harness connector may have a problem.

The P0420 code may be getting set because of a bad coil pck.


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## smj999smj (Jan 1, 2006)

Contact Nissan to see if there are any "open" campaigns or recall for your car. The cam/crank sensors were recalled in those vehicles.


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## amistry (May 30, 2011)

@rogoman - Thanks! I will try that..and report back..
any pictures or guides on how to change sensor (p0335)?


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## amistry (May 30, 2011)

smj999smj said:


> Contact Nissan to see if there are any "open" campaigns or recall for your car. The cam/crank sensors were recalled in those vehicles.


called Nissan but CSR said this VIN is not under recall


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## rogoman (Dec 16, 2004)

amistry said:


> @rogoman - Thanks! I will try that..and report back..
> any pictures or guides on how to change sensor (p0335)?


The crankshaft position sensor is located on the cylinder block rear housing facing the gear teeth (cogs) of the signal plate at the end of the crankshaft. To remove it, disconnect the harness connector and the single bolt that secures it to the block.


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## smj999smj (Jan 1, 2006)

Personally, I prefer to replace both the cam and crank sensors at the same time, as both have been problematic. You can get them both together in Nissan kit #23731-6N225. Just note that while both sensors look the same, a white paint mark identifies the crank sensor. For a good guide to installation, get a hold of Nissan technical bulletin #NTB03-124.


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## amistry (May 30, 2011)

still haven't gotten enough time to fix my car, but I haven't been driving much.
i drove my car after installing new coils almost a week later and noticed something strange. 
this time code reader showed only p0420 and no more p0335! also for some reason every time i started fan, ac was also turning on!

again didn't drive for next 2 days and today fan was just fan and ac was working like normal but still it shows p0420!

shall i still change crankshaft and cam sensors? what could be causing p0420?
thanks!


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## smj999smj (Jan 1, 2006)

P0420 is a three way catalyst code. It typically means the catalytic converter needs to be replaced.


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## amistry (May 30, 2011)

smj999smj said:


> P0420 is a three way catalyst code. It typically means the catalytic converter needs to be replaced.


how hard is it to do on my own? how much is it going to cost me?
man i am fed up of this junk...its like one after the other!


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## smj999smj (Jan 1, 2006)

I can't speak for your mechanical abilities. The catalytic converter, P/N: 14002-8J008, is part of the exhaust manifold, which MSRP's from Nissan for $520 (AAA Nissan Parts has it for $393+$140 core). Labor guide shows 1.5 hour labor. You'll need an oxygen sensor socket. The job isn't too bad if the bolts that hold on the heat shield aren't rusted up.


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