Nissan Repair: Nissan Pathfinder 1998 - Diagnostic Codes., nissan pathfinder 1998, gas vapors

Question
Hello,

Thank you in advance for your time, and expertise.

I am the only owner of this Nissan Pathfinder, and it had been a very good vehicle.

Engine Service Soon Light had been running on and off for last two years, and I finally had it diagnosed it (I had been doing other more serious maintenance projects first - like replacing timing belt, water pumps, thermostat etc..)

So this is a list of codes and their description:

1. P1448 undefined code.

2. P0325 Knock Sensor 1 Circuit ( Bank 1 or Single Sensor)Circuit Malfunction.

3. P0440 Evaporative Emission Control System.

If you could please explain each code meaning in detail, also how to correct these problems and indicate which would be the most important and if needed to be corrected immediately.

Also, if you could explain what problems could developed, since I did not tackle these problems right the way.

Additionally, if you would be so kind and instruct me on challenging these problems - if they can be done by me, what tools and parts would be required, and time needed.

I’m in possession of Haynes Service Manual for this vehicle, I am very handy, but not too experienced with cars, do not have access to garage, and have some tools, and would have access to more specialized ones if needed.

Thank you again very much,

Mike.  

Answer
Mike,

The P1448 is an evaporative fault that is linked to the charcoal canister.  This is the black plastic box that holds gas vapors from the gas tank.  Cars since 1974 have had sealed gas tanks.  Yours is detecting a leak or the valve that allows the gas vapors to be burned off at startup is stuck.  The P0440 is related and that one is probably a cracked hose or loose clamp.  From my experience, I would drop the gas tank and inspect the hoses from the fuel tank to the chassis.  Then, follow the lines to the front looking for a cracked line or loose clamp.  The P0325 is the knock sensor and this is a common problem that just means the knock sensor needs to be replaced.  Once all of this is done clear the codes and you should be fine.