service engine soon light

I have a 1998 Nissan Maxima GXE. I purchased it July of 2003. It looks and runs great. It has 38,000 miles on it. A few months after I bought it the service engine soon light came on. I took it to my faithful garage and had it serviced. They said it was possibly a fuel leak however they could not find one. They told me to replace the fuel cap because vapors could be escaping. I replaced the fuel cap and they reset the light. The light stayed off for a day or so and came back on. Now it comes on and goes off at it's own leisure. It is a total nuisance. Does anyone have any suggestions of what the real cause could be and what I could/should do about it? Thanks!

Go to an autozone and borrow their code reader. Plug it in and come back with the code.

Well I haven't made it to Auto Zone yet but I pulled the paperwork from when I had my car serviced and the code they wrote on my bill is p0420.

P0420 is...Catalyst System Efficiency below threshold on Bank 1
May have a 02 sensor going bad...or a Cat going bad....

I went to Auto Zone and here are the new codes. 1448 and 440.

Hey! Just wanted to know if anyone knows what these codes (1448 and 440) mean?

When you borrowed the OBD-II scanner from autozone, didn't it have that little booklet that explains all the codes? That's how I figured out what my problem was

Well I had someone take it for me.The guy at AutoZone checked it and wrote down the codes and a description. I called the Nissan dealer in my area and they said that it could be any one of several compontents and that it needed diagnostic testing. Testing starts at $75.00. I guess my biggest concern is that I am unemployed and I am looking for any money saving tips. I have a feeling that testing is the only way to go in this situation.

Hey! Just wanted to know if anyone knows what these codes (1448 and 440) mean?

Just looked up the codes for you. If you're getting those codes from a scan tool and not looking at the check engine flash code (screwdriver method) then it would be...

P1448 - EVAP canister vent control valve open
P0440 - EVAP system leak

Hope that helps.

- hito

I drive a 99 Maxima SE that I bought new. My service engine light came on right around 40,000. After spending $60 worth of diagnostic checks and confirming them with the screwdriver method, I am convinced that it has something to do with the EVAP control valve. The car's performance and mileage have not suffered and it still runs great. My light has now been on for about 70,000--3 or 4 years. I don't even see it anymore...you get use to it. If nothing's broken, it's not worth spending hundreds of dollars chasing down some computer bug.

I drive a 99 Maxima SE that I bought new. My service engine light came on right around 40,000. After spending $60 worth of diagnostic checks and confirming them with the screwdriver method, I am convinced that it has something to do with the EVAP control valve. The car's performance and mileage have not suffered and it still runs great. My light has now been on for about 70,000--3 or 4 years. I don't even see it anymore...you get use to it. If nothing's broken, it's not worth spending hundreds of dollars chasing down some computer bug.


My check engine light has been on since October 2003. I have not noticed any gas mileage issues and the car does seem to be running fine. I saw that you said that your car had the EVAP control problems as well. Did it happen to be the same codes (1448 and 440)?

My error code is 1008, which converts to scan tool trouble code: P0443.

I drive a 99 Maxima SE that I bought new. My service engine light came on right around 40,000. After spending $60 worth of diagnostic checks and confirming them with the screwdriver method, I am convinced that it has something to do with the EVAP control valve. The car's performance and mileage have not suffered and it still runs great. My light has now been on for about 70,000--3 or 4 years. I don't even see it anymore...you get use to it. If nothing's broken, it's not worth spending hundreds of dollars chasing down some computer bug.

I had a similar system on my 1996 Maxima SE as well (at around 35,000 miles). I now have 83,000 miles on it but I don't see the light on mine (once the dealer fixed it). The problem had something to do with a knock sensor (sorry I don't remember the details; it was 4 years ago). The technician at the dealer said that Nissan had actually issued a recall to fix the problem.

I had a similar system on my 1996 Maxima SE as well (at around 35,000 miles). I now have 83,000 miles on it but I don't see the light on mine (once the dealer fixed it). The problem had something to do with a knock sensor (sorry I don't remember the details; it was 4 years ago). The technician at the dealer said that Nissan had actually issued a recall to fix the problem.

Have any clue or any receipts that say what the check engine code(s)was? Also. any clue how long they will replace recalled parts? My car is not new in years but the mileage is only 38,000 miles. In my opinion that is still a new car.

P1448 - EVAP canister vent control valve open
P0440 - EVAP system leak

I had a similar problem, there is a valve mounted on the square canister of the EVAP system that stores the fumes from the gas tank. This valve is normally closed and opens ocassionally to let in fresh air and purge the canister of fuel vapors. Since this valve is somewhat exposed to water and the elements it can get stuck open or closed.
I would suggest either freeing it or changing the valve. On my 98 Maxima it is located under the rear of the auto oppisite the muffler.
This valve is mounted directly on the canister. I used to get the check engine light every few days so far its been good for 3 weeks. If my trouble happpens again I will change the valve. You can test the valve by connecting it directly to you car battery. Thsi will cause it to open and close.