How To Test The Ford Mass Air Flow (MAF) Sensor

Testing the Ford mass air flow (MAF) sensor on all of the Ford, Lincoln and Mercury cars and trucks is a very simple examination that tin can exist done without a scan tool. All y'all need is a multimeter. I recommend using a digital multimeter merely an analog multimeter can also exist used.

Ford has used a Hot-Wire type mass air flow sensor for many years that either comes with or without an internal air temperature sensor. If the MAF sensor has 6 wires, then this is a expressionless giveaway that it has the air temp sensor integrated inside. If the Ford MAF sensor on your automobile has four wires, then it does non have an air temp sensor integrated inside it (the air temp sensor volition be somewhere on the air duct that connects the MAF sensor to the throttle body or somewhere on the intake manifold.

Annotation: There are several different Ford MAF sensors types. These come in either a black or lite gray trunk and with half-dozen or 4 wires in the connector. Regardless of what color trunk the MAF sensor has or the corporeality of wires in the connector, they are all tested in the same style!

En Español You can find this tutorial in Castilian here: Cómo Probar El Sensor De Flujo De Aire (Sensor MAF) de Ford (at: autotecnico-online.com).

If your Ford or Mercury vehicle uses the MAF sensor in the round Canister Air Filter assembly, go hither: Ford MAF In Round Canister Air Filter Assembly.

Common Symptoms Of A Bad Ford MAF Sensor

This is not the nigh definitive listing on the subject, merely does encompass the majority of symptoms I've seen on these types of Ford mass air period sensors:

  1. MAF Codes that calorie-free upwardly the check engine light (CEL) on your musical instrument cluster.
    1. P0102 MAF Signal Low Input to PCM.
    2. P0103 MAF Signal High Input to PCM.
    3. P1100 MAF Circuit Intermittent Voltage Input.
    4. P1101 MAF Sensor Circuit Output Voltage low During KOEO Self Exam.
  2. MAF sensor malfunction that DOES Not light upwardly the cheque engine light (CEL).
  3. Lean and/or Rich code(s).
  4. Fuel Trim lawmaking(s).
  5. A tremendous lack of ability upon acceleration.
  6. Blackness smoke coming from the tail-pipe.
  7. Bad gas mileage.
  8. Vehicle may idle rough and stall.

Is The MAF Sensor Just Dirty?

The most common ready I've performed on the majority of MAF sensor bug on Fords have been cleaning information technology. Now, the symptoms that accompany a muddy (contaminated) Ford MAF sensor are non that harsh or noticeable on engine performance (of course this is non an absolute truth).

What I hateful is that a dirty MAF sensor doesn't wreak a lot of havoc on the auto or truck. Commonly the biggest complaints are bad gas mileage and/or a slight lack of ability. So how exercise I diagnose a dirty/contaminated Ford MAF sensor? Well:

  1. I'll remove it (earlier I starting time any testing) and heart-ball the 2 'hot-wires' to run across if they are covered in fuzz or other material (yous can run into an example of this here: Muddied MAF Sensor Example).
  2. Or, I'll test it first post-obit the guidelines set in this commodity, to see if it'southward producing a MAF signal.
  3. If it is producing a signal, but the indicate'southward response is too slow to changes in throttle position, then I know to look into cleaning it.
  4. If you need to clean it, here'due south the article: How To Clean The Ford Mass Airflow Sensor (at troubleshootmyvehicle.com).

Why does it become dirty/contaminated? Well, this MAF sensor easily becomes contaminated with dirt and stuff from the air filter not performing its chore or the box that holds the air filter is broken or not sealing correctly. The Ford MAF sensors are some of the easiest MAF sensor to clean. All it takes is to remove the two torx caput screws that concord information technology in place and spray-clean the two hot-wires with a MAF sensor Cleaner.

Air Leaks

The second well-nigh common problem I have encountered on virtually Fords (Mercurys and Lincolns) over the years is air leaks between the MAF sensor and the throttle body.

It is crucial, yep very disquisitional that you offset check that there are no air leaks between these two. Air entering later on the mass air flow sensor into the engine will negatively touch on fuel injection. And will skew the results of your tests which could outcome in the replacement of a adept MAF (and in the process throwing money abroad).

How do you check for air leaks? With your eyes and hands. That'southward correct, no special tools required. Just eyeball and physically shake/motion the ducting to see if it's loose or disconnected.

MAF Sensor Circuit Descriptions

Whether your Ford, Mercury or Lincoln auto has a MAF sensor with 4 or six wires (coming out of the connector) their circuits share the circuit descriptions.

Photo one of ii, in the image viewer, is that of a iv wire MAF sensor. This is a non intake air temp (IAT) sensor MAF sensor.

Photo 2 of two is of a MAF with vi wires, since it has the IAT sensor integrated with the assembly.

You'll observe that the photos (in the paradigm viewer) have the MAF connectors lettered A thru' F (If you await closely at the MAF sensor housing, you'll run into these letters on information technology likewise). I'll be using these letters for the circuit descriptions.

Here's the clarification of each circuit below:

  1. Letter F:
    1. Intake air temperature (IAT) sensor circuit (non applicable if you have a 4 wire MAF sensor).
  2. Letter D:
    1. MAF Signal.
  3. Letter C:
    1. Ground that the ECM provides.
  4. Letter B:
    1. Basis.
  5. Alphabetic character A:
    1. 12 Volts.
  6. Letter East:
    1. Air Temp. sensor excursion (not applicable if you have a four wire MAF sensor).

Using a wire-piercing probe is the most effective and easy style of getting to the MAF point, since you don't hazard damaging the female terminals of the connector by probing them directly. If you need to see what this tool looks similar, click hither: Wire-Piercing Probe. Independent of the method y'all use, be careful not to damage the wire or the female final. Accept all safety precautions.

Another important thing to notation is that the color of the wires (coming out of your Ford, Lincoln or Mercury machine or truck) does not matter. In other words, the circuit description/job of the wire is the same regardless of Make/Model and color of the wire.

IMPORTANT: All of the tests are ON CAR TESTS, do not remove the mass air flow sensor from the vehicle or from its plumbing.

Summary Of The MAF Sensor Tests

OK, you lot're gonna' start by checking the basics. These are 12 Volts and battery Ground to the MAF sensor. After that, we'll examination the actual performance of the MAF sensor as the engine is running. Utilise a digital multimeter for all tests where a multimeter is chosen for.

The MAF sensor produces an analog voltage betoken. This MAF betoken'due south DC voltage is directly related to amount of air the engine is animate. Therefore, if the engine is breathing in more air at 2500 RPM'due south that at an idle of 900RPM's the voltage output will be greater at 2500 RPM's than at idle.

Now, when testing this voltage signal, the important thing to know is not an actual Volts number at a specific RPM, merely to await for crazy and farthermost fluctuations in the voltage signal that exercise not correspond to the actual air intake (RPM's) of the engine or no signal at all. For example: If at Idle the voltage reading starts to spike up and down without you accelerating the engine or if there's no bespeak at all.

In the TEST iv section of this article, I'll testify how you lot'll use a base of operations voltage reading at idle from the MAF sensor that will assist you to confirm that the MAF sensor is bad or not.