How To Test The MAF Sensor (1997-2001 3.0L V6 Toyota Camry)

TEST 2: Making Sure The MAF Sensor Is Getting Ground

So far, you've confirmed MAF sensor is getting 10 to 12 Volts from the BLK/YEL wire (TEST 1).

In this test section, we're going to make sure that it's getting Ground. The wire that provides this Ground to the MAF sensor is the red with black stripe (RED/BLK) wire of the MAF sensor's 5-wire connector.

This Ground is not a chassis Ground, it's provided by the PCM internally and only when the key is in the ON or RUN position.

CAUTION: Be careful not to connect this wire to 12 Volts from the battery or you'll fry the PCM. The multimeter voltage test I'm suggesting in the instruction below is a safe way to check for Ground in the RED/BLK wire.

Let's get started:

1. 1

   Disconnect the MAF sensor from its electrical connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

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

4. 4

   Probe the female terminal that connects to the wire labeled with the number 3 with the black multimeter test lead.
   
   NOTE: Double check that the terminal you're testing connects to the RED/BLK wire.

5. 5

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

6. 6

   Your multimeter should display 10 to 12 Volts DC.

Let's interpret your multimeter test result:

CASE 1: Your multimeter registered 10 to 12 Volts. This is the correct and expected test result and it indicates that the MAF sensor is getting Ground from the PCM.

The next step is to test the MAF signal, go to: TEST 3: Testing The MAF Signal With A Multimeter.

CASE 2: Your multimeter DID NOT register 10 to 12 Volts. Check that all of your multimeter connections are connected securely and try the test again.

If still no voltage, then this result exonerates the MAF sensor as the cause of the MAF code lighting up your check engine light (CEL) or MAF issue, since without this Ground, the MAF sensor will not produce a signal to the computer.

Finding and repairing the cause of this missing Ground will resolve the MAF sensor issue with your Toyota Camry.

TEST 3: Testing The MAF Signal With A Multimeter

For our last MAF sensor test, we're gonna check the output signal of the MAF sensor as we rev-up the engine.

To do this, will connect our multimeter to the pink (PNK) wire of the MAF sensor connector. The PNK wire is the MAF signal output wire.

What we need to see, is for the MAF voltage to hang around 1.2 Volts DC when the engine is idling and for that voltage signal to increase when we accelerate the engine.

If math sensors defective, the voltage value will stay stuck in one value no matter how much we accelerate or decelerate the engine.

IMPORTANT: The MAF sensor must be connected to its connector to perform this test. To access the MAF signal in the wire, you'll need to use a back-probe on the connector or a wire piercing probe on the wire. To see an example of this tool and where to buy it, go here: Wire-Piercing Probe.

These are the test steps:

1. 1

   Place your multimeter in Volts DC mode.

2. 2

   Reconnect th MAF sensor to its electrical connector.

3. 3

   Probe the MAF sensor wire labeled with the number 5 in the photo with the red multimeter test lead.

4. 4

   Connect the black lead to the battery negative (-) terminal.

5. 5

   Crank and start the already warmed up engine.

6. 6

   Note the Volts DC reading on your multimeter as the engine idles.
   
   This reading may fluctuate a bit, but no matter what the instability in the reading, this will be your base voltage reading.

7. 7

   Manually accelerate the engine. The voltage reading on your multimeter should increase.

8. 8

   Let the engine return to idle. The voltage value on the multimeter should return to the base voltage value you recorded in step 5.
   
   This voltage reading may not be the exact same but should be very close.

9. 9

   Repeat this as often as you need to verify that the voltage value increases/decreases when you accelerate/decelerate the engine.

Let's interpret your multimeter test result:

CASE 1: The voltage reading increased and decreased smoothly. This test result confirms that the MAF sensor is working correctly.

CASE 2: The voltage value stayed stuck in one number. This test result tells you that the MAF sensor is bad if you have:

• Confirmed that the MAF sensor is getting power (TEST 1).
• Confirmed that the MAF sensor is getting Ground (TEST 2).
• Confirmed that the MAF sensor's output voltage signal is stuck in one number as you accelerate/decelerate the engine (this test section).

More 3.0L Toyota Camry Tutorials

You can find a complete list of 3.0L Toyota Camry tutorials in this index:

• 3.0L Toyota Camry Index of Articles.

Here's a sample of the tutorials you'll find there:

• How To Test Engine Compression (1992-2006 3.0L V6 Toyota Camry).
• How To Test For A Blown Head Gasket (1992-2006 3.0L V6 Toyota Camry).
• How To Test The TPS (1997-2001 3.0L V6 Toyota Camry).
• How To Test The Alternator (1997-2001 3.0L V6 Toyota Camry).