DTC P0102 – How To Test a 4.6L Ford MAF

DTC P0102 – How To Test a 4.6L Ford MAF


If the check engine light is triggered in your 4.6L Ford and the code comes back as a OBDII DTC P0102, our How To Test a 4.6L Ford MAF guide can come in handy. Because your Ford PCM drives your 4.6L engine based on the values being sent by the Mass Air Flow (MAF) Sensor, your car or truck will run roughly because of the OBDII P0102 trouble code.

Today we’ll be showing you how to fix the OBDII P0102 trouble code in a 1999 Ford Expedition, with a VIN code of B.


While we’ll be showing you how to test this 4.6L Ford MAF in this truck, our how to test a 4.6L Ford MAF guide also applies to the following 4.6 L equipped vehicles:

  • 1997 – 1999 Crown Victoria
  • 1997 – 1999 Ford E-150
  • 1997 – 1999 Ford E250

The specific error behind this troublesome check engine code is Mass or Volume Air Flow Circuit Low Input. This means that while your MAF sensor may be getting power and ground, it’s not sending the right signals to your ECU. Without these values or at least a Karman or Air flow voltage reading that’s within the specifications, your 4.6 L Ford may run rough.


Symptoms of P0102 – Ford – Mass or Volume Air Flow Circuit Low Input

  • Check Engine Light ON
  • Poor Idle
  • Fluctuating Idle
  • Poor performance

Before beginning our how to test a 4.6L Ford MAF DIY Guide, you may want to remove and clean your mass air flow sensor. While we don’t personally believe in MAF cleaners here at Pro Street, they can be handy in eliminating check engine lights. It’s usually best however to use an air compressor to clear the pathway of your mass air flow sensor.

The part number for your 4.6 liter Ford MAF is F6XA-12B579-AA, and this mass air flow sensor can also be listed under these interchange numbers:

  • F6XZ-12B579-AA
  • F7XZ-12B579-AA
  • F7XZ-12B579-AARM

If these numbers aren’t in stock, you can also check with your local Nissan dealer under part number 22680-1B000.


To begin our how to test a 4.6L Ford MAF, you will need to open your hood and locate your air canister. This round canister holds your Mass Air Flow sensor housing, and must be unplugged and taken apart before you can test.


Begin the guide by disconnecting the vacuum lines that run from your intake snorkel to your 4.6 Ford engine. To disconnect this line, unfold the green tab and gently pull up.


Locate your intake canister and dislodge the unit by undoing the metal clamp that holds the two halves together.


Now with this clamp loosened, you can remove your intake snorkel, MAF housing and air box for your 4.6L Ford. Before you can remove the rest of your intake snorkel, make sure to loosen the worm clamps that hold your intake pipe to the throttle body of your Ford Expedition.


Now slide off the intake pipe and flip your air box upside down. There should be a large black weatherproof plug with four wires leading into it. This is your MAF connector. Carefully pull out the rubber plug and disconnect your MAF connector by depressing the clip. Refer to the chart below for the pinouts to your 4.6L Ford MAF.


Connect the black lead of your multimeter to the negative terminal of your battery. You will be testing for power by testing the ENGINE harness side of the MAF connector.

This would be the RED wire or PIN 4 of your 4.6L Ford MAF. This should return voltage when you probe the front of the MAF connector with your multimeter. Remember, you never force or push the lead of your multimeter down the plastic housings, otherwise serious damage may occur.

If you have voltage at this wire, and you should given your OBDII DTC trouble code of P0102, check for ground. The low reference ground signal is the tan wire with blue stripe for the PCM provided ground, which is PIN 2. If you do not have ground at this wire, you’ve got bigger problems because many of your other sensors are not grounded if this one is not returning a low reference signal.

Is your 4.6L a Ford Mustang? Check our guide here to testing the Mustang MAF


This four wire 4.6L Ford MAF also comes with a chassis ground, which is black wire with white stripe. If you lack a ground here, chances are you have a loose engine ground or groundstrap. The chassis ground for our Ford Expedition is PIN 3.

The last leg of our how to test a 4.6L Ford MAF DIY Guide details testing the signal wire of your 4.6L Ford MAF. This wire is light blue with a red stripe, and this represents the MAF signal wire to your ECU.

How To Measure MAF Voltage in your 4.6L Ford MAF


  1. Start the engine, allow to warm up
  2. Shut off engine, remove key from ignition
  3. Put red lead of multimeter to PIN 1 of your connected Ford MAF. You should be backpinning this wire and reconnecting your intake pipe and MAF.
  4. Put black lead of multimeter to negative battery terminal
  5. Set multimeter to VOLTS DC mode.
  6. Measure voltage by turning the engine on. Keep hands and clothing free and clear from fans or belts.
  7. With engine at 1500 RPM, you should see a MAF Voltage between 1.2-1.5 volts
  8. Raise the engine speed to 3000 RPM, which should reply with a voltage between 1.6-1.9 volts.
  9. Release accelerator and allow engine to idle
  10. Measure MAF signal, which should be between .9 to 1 Volt DC.

If your MAF sensor is still good, you should see a even, uniform rise and fall of your MAF voltage. There should not be any spikes or weird surges in the voltage signal, and it should rise and fall along with your 4.6 L Ford engine. If your voltage doesn’t fall within these parameters, you’ll need a replacement and a scan tool to clear your OBDII trouble codes.

Have any questions about our how to test a 4.6L Ford MAF DIY Guide? Leave us a message below and let us know!


  1. Great write up fellas. Quick question I got a Ford windstar with the same code. Do u guys have a map sensor pinouts? Thx prostreet.