O2 sensors

BOBTHERRIEN

MEMBER
FORD TAURUS

2002 taurus, 3.0 v6
Reading thru the threads the one about the mass air flow sounds like the issues I have experienced. I saw the thread below:

And I have been thru this process except I have been under the car and am told there are only 3 sensors. Was getting upstream codes, replaced those, code went away, except too rich, then code bank 2 sensor 2 replaced and is still issue. And causing error code. As well as too rich code too.

I'm being told to perhaps check fuses and relay as a possible cause. I don't have a manual. Could anyone tell me which number fuse or relay has to do with the 02 sensors?

This was a thread that sounded just like my issue.
Question: 2002 Ford Taurus mileage: 60,000. The check engine light on my Taurus came on recently and when scanned the codes indicated a bad heated O2 sensor circuit. Assuming the O2 sensors needed replaced, I purchased the 4 sensors from a local chain auto parts dealership. Upon replacing the O2 Sensors, I cleared the codes and drove a short distance. The check engine light came back on, when I checked the codes; they were identical to the codes before replacing the O2 sensors. Is it possible I received 4 bad sensors from the parts supplier? I'm assuming at this point, this is unlikely and am wondering what else may cause the O2 sensors to fail to send data?

Answer: A mass air flow sensor is probably the culprit. A faulty air-flow sensor affects the fuel mixture which is read by the O² (oxygen) sensors.

Thanks,

Bob

1 Reply

BLMO

MEMBER
72 POSTS

I agree. Computers are like weathermen. They are only right about 50% of the time.

I'll take it a little further, though. I won't even read the codes until I have looked at the low-tech problems, such as vacuum leaks, spark plugs, etc. I have seen too many false positives, especially with O2 sensors and EGR problems.

I have learned that, if you get an O2 sensor error, especially if all of them set a code, then it is probably something else. Same with EGR. To this day, I have yet to actually have a bad O2 sensor on any of my old cars, although I always get the code.