CEL is on don't know where to start?

[newstylecustoms]

My wife's 02 4 door with 4.0L has the check engine light on now. It has 72000 miles on it. The codes are P0014, P0000 and C0000. Any ideas where to start with this. I am assuming there is some kind of EGR problem but I don't want to just throw parts at it.

Thanks in advance.

 

[glfredrick]

I'd start by actually scanning the engine while it is running to make sure that your O2 sensor is reacting, that your fuel trim is correct, and that the EGR is opening and closing correctly.

After that, I'd pull the EGR and clean it with choke cleaner spray. I'd do the same for the IAC valve. Then, clean the mass air flow sensor with the proper cleaner for it and see what happens.

Oh, BTW, an O2 code doesn't always mean that the O2 sensors are bad... Typically it means that the computer is seeing a number that is out of spec, not a bad sensor (the computer can't even diagnose a bad sensor -- only a bad reading!). Same goes for every other component, which is why codes are only a good place to start, for actually looking at stuff to figure out the real problem.

 

[newstylecustoms]

I had my numbers switched the code was P1400. I noticed tonight after filling the gas tank the code went away, same was true last week when it came on.

 

[glfredrick]

Get a new gas cap. The o-ring that seals the tank is leaky, and that will set a code.

In the first 10-20 seconds after start up, a small pump hidden in one of the secret black boxes on your Explorer pumps air into the tank to test the integrity of the system, then reports to the computer any leaks. This is true of virtually all OBD II systems. Yours has a leak somewhere, and most typically it is the gas cap. It could be a vacuum line also.

The typical test I use for vacuum lines is a short (very short) burst of starting fluid in the area of vacuum lines and connections. If the engine revs up, you have a leak that needs attention. Obviously, you do not flood the engine compartment with starting fluid! That could end up with nasty consequences. Short bursts around a line won't hurt anything, however, and that is the best method I've found for locating leaks. Note that the spray method won't work on the gas cap -- too far away from the engine.

 

[newstylecustoms]

Great idea on the vac lines. I think the gas cap light would come on if the cap wasn't sealing properly. Maybe not.