I have a 99 Explorer 4.0L OHV with a check engine light on. The codes came out as needing a MAF sensor. I went to Auto Zone and they sell Cardone MAFs for $127. Should I replace the MAF with this part or go to the local Ford dealer and get a factory OEM MAF to replace with?

 

Personally, I'd go with NAPA or Motorcraft (Ford OEM). But first: What were the codes? Are you sure that the MAF needs to be replaced? There is a thin wire inside the sensor. Is it broken?

Second, a number of folks have successfully cleaned MAFs and returned them to service. I'd try that first before replacing it.

Good luck!

 

Well, I made the mistake of not writing down the codes that Auto Zone pulled. I will go back tomorrow and get the codes again. If that thin wire inside the sensor is broken, will the whole sensor unit need to be replaced? What is the best way to clean the thing? Thanks!

 

Yes - if the wire is broken, the sensor is toast. I've never cleaned one myself, but you can do a search and find out how other folks did it. I think that you should use something that won't leave a residue, like electrical contact cleaner.

Good luck!

 

Once the sensor is cleaned, will that automatically clear the codes and the check engine light? Or, do I need to disconnect the battery for 10 minutes to accomplish this?

Also, if that isn't the problem, can I get the codes downloaded from Auto Zone before the check engine light reappears?

 

I got the codes....They are P0171 and P0174. The Auto Zone printout said something about fuel running too lean in a couple cylinders. Any ideas? MAF needs replacing? O2 sensor? Leak somewhere?

 

No, you'll have to clear the codes. What I would do is to clear the codes, then reinstall the sensor once you've cleaned it - assuming that the wire isn't broken. If the wire is broken, you'll need a new MAF in any case. If the MAF sensor isn't your problem, the light will come on again.

Before you do anything, go back to AZ and have them read the codes again. Post them here and then we can help you determine if the MAF sensor is indeed the problem, or if it could be something else.

Kevin

 

I think I posted at the same time you did. The codes are:

P0171 and P0174.....something about the fuel running too lean in bank 1 and bank 2.

 

Those are O-2 lean codes for both banks.

Most likely problem is a vacuum leak somewhere.

Click on "search this forum"& do a search on "lean codes"

Should find LOTS of threads on this.

 

Ford factory OEM XF2Z12B579ABRM FTE $90.53 exchange!

if you need one let me know.

Ed

 

Autozone must sell thousands of unneeded oxygen sensors and MAF sensors based on P0171. The oxygen sensor is a "wear item", so if it has 100000 plus miles it is not unreasoanble to replace it. It might actually fix the problem, perhaps 40 percent of the time. A failed MAF sensor is much more rare. The guy at that store is more aggressive than most in selling you parts you don't need.

The last time I tracked one of these P0171 codes down (on a Ford Escort), it proved to be a rubber PCV hose that was cracked right at the connection to the engine. It created an intermittant vacuum leak -- the engine had to shift in the mounts before the leak would show itself.

So I'm with the other guys -- your code is probably a vacuum leak. This is much easier to track down with a product like autoenginuity than making the trips to Autozone.

 

Well, I cleaned the MAF with electric contact cleaner and have driven 100-150 miles since with no CEL. Maybe that was the issue? We'll see. How long does it normally take for the CEL to re-appear after the codes have been reset?

 

Excellent news. I'm pretty sure that the light would have come back on by now. Glad to hear that you fixed it for the price of a can of contact cleaner!

Kevin

 

How long it takes to reset the code depends on how severe the problem is and your driving habits. If the problem was "marginal"... basically ON the line of bad/not bad it may take months to set again. If the problem was SEVERE.. then it should have come back on by now.

It's quite likely that cleaning the MAF fixed your problem... so if that is the case it is FIXED and you can relax.

If for some reason it sets the lean codes yet again, I would strongly suspect a vacuum leak... check all vacuum lines and hoses for breaks, cracks, etc... and if nothing is found try spraying carb or intake cleaner around the intake manifold and listen for a change in idle. If nothing found then.. then replace the intake gaskets.

But lets not jump the gun just yet... feel free to keep driving and we'll worry about it if the light ever comes back on.

Good luck

 

I didn't know that it could take that long for the CEL to come back on. Thanks for the tip, MazdaRangerGuyInSTL!