How To Test The MAF Sensor (2000-2003 3.0L V6 Ford Taurus, Mercury Sable)

Testing the mass airflow (MAF) sensor on the 2000–2003 3.0L V6 Ford Taurus (Mercury Sable) to see if it has failed isn't difficult, and you don't need any expensive diagnostic equipment to do it.

In this tutorial, I'm going to show you how to test the MAF sensor with a multimeter (no scan tool needed). The tests include checking the MAF signal output, confirming it's getting power (VPWR), and making sure it has Ground (PWR GND and MAF RTN).

Once you've run all your checks, you'll know if the MAF sensor is good or if it's toast and needs to be replaced.

APPLIES TO: This tutorial applies to the following vehicles:

• 3.0L V6 Ford Taurus: 2000, 2001, 2002, 2003.
• 3.0L V6 Mercury Sable: 2000, 2001, 2002, 2003.

1991-1999 MAF SENSOR TESTS:

• How To Test The MAF Sensor (1991-1995 3.0L V6 Ford Taurus, Mercury Sable).
• How To Test The MAF Sensor (1996-1999 3.0L V6 Ford Taurus, Mercury Sable).

Symptoms Of A Bad MAF Sensor

As you're probably already aware, the mass airflow sensor measures the amount of air entering the engine. Your Ford Taurus or Mercury Sable's PCM then uses this information to determine how much fuel to spray into each of the six cylinders.

So, when the mass airflow sensor fails and the PCM doesn't get a correct MAF signal, it can't fine-tune the fuel delivery. The end result is poor engine performance, and you'll see one or more of the following symptoms.

• Check Engine Light: The CEL will be lit on the dash, and the computer will usually store one of these codes:
  • P0102: MAF Sensor Signal Low.
  • P0103: MAF Sensor Signal High.
• Lack of power: Your Taurus or Sable's engine may feel weak or hesitate when you hit the gas, especially under load or at higher speeds.
• Rough idle/stalling: The engine can idle unevenly or shut off on its own.
• Bad gas mileage: A bad MAF affects the PCM's ability to control the air-fuel mixture, making the engine run rich or lean, which kills gas mileage.
• Black exhaust smoke: If the PCM is adding too much fuel because of a bad MAF sensor signal, you may see black smoke coming out of the tailpipe.
• Hard starting: Sometimes the engine will crank but struggle to start.
• Hesitation or surging: You might feel the engine stumble or surge while accelerating or cruising.

MAF Sensor Circuit Descriptions

The MAF sensor on your 2000-2003 3.0L V6 Ford Taurus or Mercury Sable uses a 6-pin connector and with 6 wires come out of it. In the table below, I'm providing a brief description of what each wire circuit does so you can use that info in the test instructions that follow:

Pin	Wire	Description
1	Gray with red stripe (GRY/RED)	IAT –Intake Air Temp Sensor Signal
2	Red (RED)	VPWR –12 Volts Input in RUN or START
3	Black with white stripe (BLK/WHT)	PWR GND –Chassis Ground Input
4	Tan with light blue stripe (TAN/LT BLU)	MAF RTN –MAF sensor Ground (provided by PCM)
5	Light blue with red stripe (LT BLU/RED)	MAF –MAF signal
6	Gray (GRY)	SIG RTN –IAT sensor Ground

Where To Buy The MAF Sensor And Save

The following MAF sensors are of known automotive brands (brands that I use myself):

NOTE: Not sure if the indicated MAF sensors fit your particular 2000-2003 3.0L V6 Ford Taurus or Mercury Sable? Don't worry. Once you get to the site, they'll ask you for the specifics of your particular vehicle. If it doesn't fit, they'll find you the right one.

TEST 1: Testing The MAF Signal

The MAF sensor is designed to react to the amount of air the engine is taking in. In a nutshell:

• When engine RPM is low and airflow into the engine is low, the MAF sensor produces a low voltage signal (around 1 Volt).
• As engine speed goes up and airflow increases —like when you step on the gas pedal— the MAF sensor's output signal also increases.

This is how the PCM knows that air intake is increasing or decreasing, depending on how much you step on or off the gas pedal.

When the sensor fails, its signal voltage will usually stay stuck at one value, no matter how much RPM or airflow changes.

So, for our first test, we're going to tap into the MAF signal wire with a multimeter and check the signal voltage output.

IMPORTANT: The MAF sensor must remain plugged into its connector while doing this check. You'll need to back probe the connector or pierce the wire with a probe. This is the same tool I use and recommend: Goupchn 4mm Banana to Banana Plug Test Leads Kit (Amazon affiliate link).

Here's how to begin the test:

1. 1

   Set your multimeter to Volts DC.

2. 2

   Attach the black multimeter lead to the battery's negative (-) post.

3. 3

   Hook the red multimeter lead to the light blue with red stripe (LT BLU/RED) wire using the right probing tool.
   
   This LT BLU/RED wire connects to terminal number 5 on the MAF sensor connector (see diagram above).

4. 4

   Start the engine and let it idle.
   
   Once the idle evens out, take note of the voltage reading on your meter. It may bounce around a little —and that's normal. This initial number is your base MAF signal voltage.

5. 5

   Accelerate the engine by opening the throttle.
   
   You can do this by moving the throttle linkage at the throttle body or by having a helper step on the gas pedal.

6. 6

   The MAF signal voltage should climb as RPM goes up.

7. 7

   Release the throttle to bring the engine RPM back down.

8. 8

   The voltage should drop as the RPMs come down.

9. 9

   Repeat the rev-up/release test several times to confirm the results are consistent.

Here's how to make sense of your test result:

CASE 1: The signal voltage increased as engine speed went up and dropped as you let off the throttle. That's the correct behavior and it confirms the MAF sensor is doing its job.

If you've got a stored P0102 (MAF Signal Low) or P0103 (MAF Signal High), then the condition that triggered those codes isn't present right now —since the signal is reacting to RPM changes instead of being stuck too high or too low.

CASE 2: The signal voltage stayed locked on one value no matter how the engine speed changed. This usually means the MAF sensor has failed.

Before condemning the sensor as bad, a couple more checks are needed. For the next step, go to: TEST 2: Making Sure The MAF Sensor Is Getting Power (VPWR).

TEST 2: Making Sure The MAF Sensor Is Getting Power (VPWR)

The MAF sensor on your Taurus or Sable needs 12 Volts to function, and this power is available when you turn the key to the RUN or START position.

In this test section, we'll check that female terminal number 2 of the MAF sensor connector is delivering 10 to 12 Volts to the sensor.

The wire going to terminal number 2 is the red (RED) wire of the MAF sensor's 6-wire connector.

To confirm the presence of these 10 to 12 Volts at the terminal, we'll do a simple multimeter voltage test.

IMPORTANT: Be careful when probing the front of the MAF sensor connector. Don't force the multimeter test lead in, because if you damage the female terminal, you'll end up having to replace the whole connector.

These are the test steps:

1. 1

   Unplug the MAF sensor from its connector.

2. 2

   Set your multimeter to Volts DC.

3. 3

   Attach the black multimeter lead to the battery's negative (-) post.

4. 4

   Lightly probe the female terminal number 2 with the red multimeter lead.
   
   Terminal 2 should correspond to the RED wire of the MAF sensor's 6-wire connector.

5. 5

   Switch the key to RUN, but don't crank or start the engine.

6. 6

   The multimeter should show 10 to 12 Volts.

Now let's go over what your test results mean:

CASE 1: The multimeter showed 10 to 12 Volts. That's the correct and expected reading.

The next step is to confirm the MAF sensor also has chassis Ground. Go to: TEST 3: Making Sure The MAF Sensor Is Getting Ground (PWR GND).

CASE 2: The multimeter did not show 10 to 12 Volts. Recheck your multimeter connections and repeat the test to be sure.

If the reading is still missing, you can rule out the MAF sensor itself —because without a solid 10 to 12 Volt supply, it simply can't operate.

Your next move is to track down why the voltage is missing on the RED wire and fix it, so the MAF sensor can function properly and the diagnostic trouble code (DTC) can be resolved.

TEST 3: Making Sure The MAF Sensor Is Getting Ground (PWR GND)

Now that we've confirmed the MAF sensor is getting power from terminal 2 (in TEST 2), the next step is to make sure it's getting chassis Ground from terminal 3.

Terminal 3 connects to the black with white stripe (BLK/WHT) wire of the MAF sensor connector.

Since this is a chassis Ground, it's available to the MAF sensor at all times, whether the key is in the RUN, START or OFF position.

To check for Ground at terminal 3, we'll do a multimeter voltage test —the same way we checked for power in TEST 2.

IMPORTANT: Be careful not to damage the front of the connector or female terminal with the multimeter test lead, or you'll need to replace the connector.

These are the test steps:

1. 1

   Disconnect the MAF sensor from its electrical connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

   Connect the red multimeter test lead to the battery positive (+) terminal.

4. 4

   Gently probe female terminal number 3 with the black multimeter test lead.
   
   Terminal number 3 should connect to the BLK/WHT wire of the MAF sensor connector.

5. 5

   You should see 10 to 12 Volts on the multimeter.
   
   NOTE: Since this is a chassis Ground, it's available at all times whether the key is ON or OFF.

Now let's break down what your results mean:

CASE 1: The multimeter showed 10 to 12 Volts. This is the expected result and confirms the MAF sensor has chassis Ground.

Next —and this is the final step— verify that your Ford Taurus or Mercury Sable's PCM is supplying sensor Ground (MAF RTN) to the MAF sensor. Head to: TEST 4: Making Sure The MAF Sensor Is Getting Ground (MAF RTN).

CASE 2: The multimeter DID NOT show 10 to 12 Volts. This indicates the MAF sensor isn't receiving chassis Ground.

Recheck your multimeter connections and repeat the test. If the reading still doesn't come up to 10–12 Volts, you can rule out the MAF sensor itself —it can't operate without the BLK/WHT wire delivering chassis Ground.

Your next move is to locate the cause of the missing chassis Ground and restore it.

TEST 4: Making Sure The MAF Sensor Is Getting Ground (MAF RTN)

Up to this point, your MAF sensor diagnostic has confirmed the following:

• The MAF signal is stuck at one voltage value (TEST 1).
• The MAF sensor is getting power (10 to 12 Volts DC) (TEST 2).
• The MAF sensor is getting chassis Ground (TEST 3).

For our last test, we're gonna make sure the airflow sensing circuit itself is receiving Ground from the PCM thru the tan with light blue stripe (TAN/LT BLU) wire. In Ford-speak, this Ground is called the MAF RTN Ground.

To check for this MAF RTN Ground, we'll use a multimeter voltage test just like in the previous three checks.

CAUTION: This Ground is provided by the fuel injection computer internally. Be careful not to connect this wire to battery 12 Volts, or you'll fry the computer. The multimeter voltage test I'm suggesting in the instructions below is a safe way to check for the presence of MAF RTN Ground in this circuit.

These are the test steps:

1. 1

   Disconnect the MAF sensor from its electrical connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

   Connect the red multimeter test lead to the battery positive (+) terminal.

4. 4

   Gently probe female terminal number 4 with the black multimeter test lead.
   
   Terminal number 4 should correspond to the TAN/LT BLU wire of the MAF sensor connector.

5. 5

   Turn the key to the RUN position but don't crank or start the engine.

6. 6

   You should see 10 to 12 Volts on the multimeter.

Let's see what your test results mean:

CASE 1: The multimeter showed 10 to 12 Volts. This confirms the MAF RTN circuit is doing its job and the PCM is supplying sensor Ground to the MAF sensor.

If you've confirmed the following, then you can conclude the MAF sensor is fried and needs to be replaced:

• TEST 1 —The MAF signal is stuck at one value, no matter the engine speed.
• TEST 2 —Confirmed, the sensor is getting 10 to 12 Volts (VPWR).
• TEST 3 —The sensor is receiving chassis Ground (PWR GND).
• This test —Confirmed, the MAF RTN circuit is delivering Ground from the PCM.

When you're ready to replace it, here's the MAF sensor from two trusted automotive brands I've used before and recommend without hesitation:

• Walker Products 245-3102 Mass Air Flow Sensor Assembly (Amazon affiliate link).
• Delphi AF10128 Air Flow Sensor (Amazon affiliate link).

CASE 2: The multimeter DID NOT show 10 to 12 Volts. This result means the MAF sensor isn't getting a sensor Ground (MAF RTN) from the PCM.

Double-check your multimeter connections and repeat the test. If the reading still doesn't come up to 10 to 12 Volts, you can rule out the MAF sensor as the problem since it cannot function without the MAF RTN Ground from the fuel injection computer.

Your next step is to figure out why this Ground is missing and restore it.

More 3.0L V6 Ford Taurus Diagnostic Tutorials

You can find a complete list of 3.0L V6 Ford Taurus and Mercury Sable diagnostic tutorials in this index:

• 3.0L V6 Ford Taurus Index Of Articles.

Here's a sample of the diagnostic tutorials you'll find in the index:

• How To Test The Fuel Injectors (1991-1995 3.0L Ford Taurus).
• How To Test The Alternator (1994-1995 3.0L V6 Ford Taurus).
• How To Test The Fuel Pump (1990-2000 3.0L Ford Taurus).
• Constant Control Relay Module Pinout (1996-1997 3.0L Ford Taurus).