Code66 MAF fault. Jricher....come on in brotha!

Code 66 MAF below minimum test voltage.
Insufficient or no voltage from MAF. Dirty MAF element, bad MAF, bad MAF wiring, missing power to MAF. Check for missing +12 volts on this circuit. Check the two links for a wiring diagram to help you find the red wire for computer power relay switched +12 volts. Check for 12 volts between the red and black wires on the MAF heater (usually pins A & B). while the connector is plugged into the MAF. This may require the use of a couple of safety pins to probe the MAF connector from the back side of it.

There are three parts in a MAF: the heater, the sensor element and the amplifier. The heater heats the MAF sensor element causing the resistance to increase. The amplifier buffers the MAF output signal and has a resistor that is laser trimmed to provide an output range compatible with the computer's load tables.

The MAF element is secured by 2 screws & has 1 wiring connector. To clean the element, remove it from the MAF housing and spray it down with electronic parts cleaner or non-inflammable brake parts cleaner (same stuff in a bigger can and cheaper too).

The MAF output varies with RPM which causes the airflow to increase or decease. The increase of air across the MAF sensor element causes it to cool, allowing more voltage to pass and telling the computer to increase the fuel flow. A decrease in airflow causes the MAF sensor element to get warmer, decreasing the voltage and reducing the fuel flow. Measure the MAF output at pins C & D on the MAF connector (dark blue/orange and tan/light blue) or at pins 50 & 9 on the computer.

At idle = approximately .6 volt
20 MPH = approximately 1.10 volt
40 MPH = approximately 1.70 volt
60 MPH = approximately 2.10 volt

Check the resistance of the MAF signal wiring. Pin D on the MAF and pin 50 on the computer (dark blue/orange wire) should be less than 2 ohms. Pin C on the MAF and pin 9 on the computer (tan/light blue wire) should be less than 2 ohms.

There should be a minimum of 10K ohms between either pin C or D on the MAF and ground.

See the following website for some help from Tmoss (diagram designer) & Stang&2Birds (website host)

http://www.veryuseful.com/mustang/tech/engine/images/fuel-alt-links-ign-ac.gif

http://www.veryuseful.com/mustang/tech/engine/images/88-91eecPinout.gif

To clean the MAF, remove the MAF element and gently spray it with electrical contact cleaner. You can also use non-flammable brake parts cleaner (same chemical in a bigger can & cheaper too). Let it dry and put it back in.

Sigh, what's the year of the engine and what are the engine mods?

To test the MAF, you'll need to do a voltage test on the MAF. Or, swap with another MAF.


Does the MIL work at all? A bad MAF should light the MIL. Did you try the test multiple times with the car on/off in between tests? I'm surprised that you got a MAF error without a MIL.

5.02GO said:

the year is 1993. The mods are listed below. I have already cleaned the elements.

No engine light. The car runs good. Codes have been cleared in the computer twice but i still get the fault. Thats what i dont understand.

I'll do a voltage test later today.

thank you.

Click to expand...

Opps, my bad. I was wondering WHEN this would happen.

You see, as of 1/06, 49% of the people still have dial-up. I'm ONE OF THEM. Unless someone will pay $10K to run a line from Verison(sp?) or pay me $60+/months for cable, they can STFU about me getting a high-speed connection.

So, Stangnet added the &&*(()*))*( ability to add stupid *ss banners to the sig. But, nit the ability to not display *just the banner*. So, I turned off the sigs.

So... What was the result of your test? Also, can you list your major mods.