so rare 65

My father owns 2000 f150 , 4.2 lt. ! Trouble code 0102 ! He has replaced this sensor three times with the same trouble code coming up average bout month inbetween ! I asked where gotton an replied cheap part from part store not to excited about due to expierance of bad electrinoc parts ! What my question is to help him is what supplies the voltage ? Ecm ? Also could it be a short in that circuit in the harness ? I feel it is cuz of after market sensor that is affecting it as to tolerance specs compared to dealer ship quility an spects !

so rare 65

Can someone please help with this ?

so rare 65

Please help !!

Bluegrass

The Mass Air meter is supplied 12 volts (through a pcm relay) in common with all the fuel injectors, IAC, intake runner control, EGR regulator and a number of other items.
One meter lead goes to ground, one to 12 volts, the other 2 go to the PCM to deliver the signal +/-.
It could be the sensor quality but the same result 3 times tells me you should look at the harness for issues.
Low cost sensors are often test rejects from the same mfger that make good ones.
Don't just jump on a code that refers to the sensor, as the only cause of the problem.
One of the best ways to look at this is with a scanner to look at the live MA data while the engine is running.
.
The air meter is a bridge circuit configured like a diamond with resistances in each leg. Three resistances are fixed, one is a heated resistance element that is cooled by air passing through and changes it's resistance as the output signal to the PCM.
A voltmeter test may be helpfull in finding the low voltage condition.
The PCM monitors the sensor for low and high voltage out of limits and sets the code when found out of limits.
Likely more than you wanted to know but someone has to know a little about what their looking for.
For test limits, look up the 'FORD' 102 code definition in 'full' and not just run with the mention of mass Air sensor. You get fooled often, that way.

Good luck.

so rare 65

Thank you for info. and advice ! That helps me out on the same info i gave to my father ! Some of it helps me as well !! appreaciate you for time and onfo. !

Bert

This test is in the Snap On Vantage if you own one but you
can still use what you have. Back probe the signal wire of
the maf connector. Put the positive lead of a scope, dmm,
or gmm on it. Don't use hertz, use volts dc. Engage the
min/max feature if you have it. Snap throttle to WOT
several times. A max voltage reading below 3.7v is a dirty
or bad maf. I have cleaned them and gotten as much as 4.0v.
New sensors read 4.2-4.4v. Most rebuilts I have seen will
read 3.9-4.0v.

In this diagram, 12v is on the gray arrow, ground is the pink arrows and the snsor reading is on the red arrows. The red arrow is where you sould get the above test results.

Attached Images

MAF.jpg (68.7 KB, 2 views)

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Bert