How To Test your Ford Excursion MAF Sensor

How To Test your Ford Excursion MAF Sensor


The mass air flow meter in your Ford diesel truck is vital to your engine. Required for your PowerStroke turbo diesel engine, this mass air flow or Excursion MAF sensor reads the incoming air charge. Sending this signal to your PowerStroke computer it allows your truck to deliver the right amount of fuel for your 6.0 liter turbo diesel.

When your Excursion MAF sensor fails on you, the PowerStroke engine won’t know how much air is entering the system. Without this information your check engine light will turn on, and your Ford truck could go into limp mode. Today I’ll be showing you how to test a Excursion MAF sensor in a 2004 Ford with a 6.0 liter PowerStroke engine in it.

In order to complete this how to testing guide, you’ll need to use a digital multimeter. Of course if your Ford check engine light is on, the tool you need to use is a OBDII scan tool to retrieve it.

The Excursion MAF sensor is mounted to the backside of your air filter housing in your engine bay. Before you begin this tutorial, it’s best if your engine is completely cold given the heat your PowerStroke turbo can generate. Open your Excursion hood and look into the engine bay to locate the mass air flow meter.

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You’ll be testing for power and signal in your Excursion MAF sensor. Before you do this you’ll need to insert the ignition key and turn it to the “ON” position. Now that your key is turned to this setting, your engine sensors should be powered up.

Unplug your Powerstroke mass air flow sensor, and you’ll be measuring for voltage at the front of the MAF connector.

Testing your Excursion MAF sensor for Power

To test for power at your Powerstroke mass air flow meter, place the black lead of your multimeter on the battery ground. Now gently probe the front of PIN 2 for the power signal to your mass air flow meter. You should read around 12 volts of DC power at this wire.

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While you are at it you might as well check for power in your PowerStroke Intake Air Temperature sensor. The power wire for your IAT sensor is a 5 volt signal, that’s located at PIN 6. Test the front of this pin and remember never to force or shove the multimeter leads into the plastic connector.

There should be roughly 4.5-5.0 volts of DC power at this wire. This is the power wire for your intake temperature sensor. Now that you’ve confirmed power at this air flow meter, the next step to is confirm the low reference ground signals

The ground signal should be present at PIN 3 and PIN 1, which are the IAT and the Excursion MAF sensor ground signals respectively. Once you have confirmed that you have power and ground at both sets of wires you can move onto the signal.

Measuring your Excursion MAF sensor for Signal

The signal wire for your mass air flow sensor can be tested only by reconnecting the MAF harness. Once this is reconnected the pin you will be checking for is PIN 4. With the harness attached to your mass air flow meter, backpin or pierce WIRE 4 with your multimeter lead.

Put the black lead on the negative terminal of your battery next. Now you should be able to read the incoming air charge and voltage. This next part of the test is potentially dangerous, so make sure to keep clear of your engine, pulleys and cooling fans. Start your engine and monitor the voltage at this wire at idle.

Take a look at the voltage from this signal wire, it should be fluctuating slightly but hover around a certain signal. Monitor the fluctuations and make sure that the voltages aren’t too far out of the spectrum. This is your base mass air flow meter signal, and from here you’ll be measuring the signal.

From here you can manually deflect the throttle body open, or have a friend rev your engine. Try to not create positive pressure through your turbocharger, and from here you should see your voltage increase. As you ease off the gas this voltage should scale back down slowly, and without gaps or spikes.

Repeat this test a few times to see if your Excursion MAF sensor responds accordingly. If it doesn’t it means you need a replacement mass air flow meter. Signs of a failed MAF sensor will result in your signal voltage spiking or going all over the place.

Replacing your Excursion MAF sensor

There’s two ways to go about this, you can either replace the entire mass air flow assembly, or simply remove the hex bolts that hold the sensor part.

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You will need safety hex tools to remove the sensor as shown above if you don’t want to buy one with a housing already attached. Browse our collection of mass air flow sensors for more details.

Have any questions about our Excursion MAF sensor DIY guide? Leave them for us below and let us know.