oxygen sensor?

[therigwelder]

my wife owns a 99 explorer the check engine light has been on for awhile so i pulled the codes .0171 and 0174 system adaptive fuel too lean and too rich what ever that means.i presumed these codes had something to do with the 02 sensor.my understanding is only the sensor nearest the manifold is the primary pcm signal sensor so this was the only sensor ive tested .now for my test results.@cold start up the sensor read .08 millivolts,@operating temp the sensor read 0.12 steady not actively fluctuating between high and low voltage(i think the correct voltage range should be .1 -.09). now if ive got my wires right B+VOLTS= RED/WHITE
HTD GND= LT BLUE/ORANGE
SIGNAL= ORANGE
GND= GREY/LT BLUE
my readings koeo are B+VOLTS- HTD GND = 0 MILLIVOLTS
B+VOLTS - GND=6.40 VOLTS
SIGNAL TO BAT- =38.2 MILLIVOLTS
i think this sensor is bad what do you all think?

 

[Ranger379]

i was told that P0171 meant that the cats where bad, i got that code a couple times and asked and i belive thats what i was told on here, it could be sensor too i guess, but u should see the looks of my cats lol...

 

[NHale623]

P0171 = System Adaptive fuel too lean (Bank 1)
P0174 = System Adaptive fuel too lean (Bank 2)

You either have a vacuum leak, or not enough fuel.

If it were mine, I'd check the fuel pressure. If it's okay, then start looking for a vacuum leak. What engine is in the truck?

 

[dynamite196]

Usually those codes point to a fuel/air mixture problem as hale mentioned, when was the last time you did a tune up?

 

[aldive]

P0171 = System Adaptive fuel too lean (Bank 1)
P0174 = System Adaptive fuel too lean (Bank 2)

You either have a vacuum leak, or not enough fuel.

If it were mine, I'd check the fuel pressure. If it's okay, then start looking for a vacuum leak. What engine is in the truck?

Sage advise; don't just go throwing parts ( O2 sensors ) at the "problem".

Good luck ....

 

[kenderish]

Anyone with these codes should read this:

http://autotechrepair.suite101.com/...ir_flow_sensors

I found this article on another forum and it explains why we get certain codes, shows that your problem may be your MAF sensor. Good article.

 

[ma96782]

http://www.explorerforum.com/forums/showthread.php?t=171556


Aloha, Mark