TEST 1: Making Sure The MAF Sensor Is Getting 12 Volts
The very first thing that we're going to do is to make sure that the MAF sensor on your 3.3L Buick or Oldsmobile is receiving 10 to 12 Volts DC.
We'll do this by doing a simple multimeter voltage test.
The wire that supplies these 12 Volts to the MAF sensor is the wire labeled with the letter C in the photo above.
Depending on the year of your specific vehicle, this wire will be a pink with black stripe (PNK/BLK) wire or a pink (PNK) wire.
If 10 to 12 Volts are present, then we'll move on to the next test.
These are the test steps:
- 1
Put the multimeter in Volts DC mode.
- 2
Disconnect the MAF sensor from its electrical connector.
- 3
With the red multimeter test lead and an appropriate tool, probe the wire labeled with the letter C.
CAUTION: If you probe the front of the female terminal, be careful not to damage it with the multimeter test lead. - 4
Connect the black multimeter test lead to the battery negative (-) terminal.
- 5
Turn key to the ON position but don't crank or start the engine.
- 6
You should see 10 to 12 Volts on the multimeter.
Let's take a look at what your test results mean:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct and expected test result.
Your next step is to go to: TEST 2: Making Sure The MAF Sensor Is Getting Ground.
CASE 2: The multimeter DID NOT register 10 to 12 Volts. Without this voltage the MAF sensor will not work.
Your next step is to find out why this voltage is missing and resolve the problem.
Once you've restored power to the wire, your MAF sensor should function again.
TEST 2: Making Sure The MAF Sensor Is Getting Ground
Now that you've made sure that the MAF sensor is getting 10 to 12 Volts, the next step is to make sure that it's getting Ground.
Ground is supplied by the wire labeled with the letter B in the photo above.
We'll also do a simple multimeter voltage test to make sure that this wire is supplying Ground to the MAF sensor.
Depending on your specific Buick or Oldsmobile, this wire will be a black with white stripe (BLK/WHT) wire or a black (BLK) wire.
If the MAF sensor is getting Ground, the next and last step is to check the sensor's Hertz signal in TEST 3.
Let's get testing:
- 1
Put the multimeter in Volts DC mode.
- 2
Disconnect the MAF sensor from its electrical connector.
- 3
With the black multimeter test lead and an appropriate tool, probe the wire labeled with the letter B.
CAUTION: If you probe the front of the female terminal, be careful not to damage it with the multimeter test lead. - 4
Connect the red multimeter test lead to the battery positive (+) terminal.
- 5
You should see 10 to 12 Volts on the multimeter.
Let's take a look at what your test results mean:
CASE 1: The multimeter registered 10 to 12 Volts. This is the correct and expected test result and it confirms that the MAF sensor is getting Ground.
Your next step is to test the MAF sensor's signal output. For this test go to: TEST 3: Testing The MAF Signal With A Multimeter.
CASE 2: The multimeter DID NOT register 10 to 12 Volts. This test result tells you that the MAF sensor is not getting Ground. Without it, the sensor won't work.
Your next step is to find out why this Ground is missing and resolve the problem.
Once you've restored Ground to the wire, your MAF sensor should function again.
TEST 3: Testing The MAF Signal With A Multimeter
All right, if you've reached this point, you've made sure that the MAF sensor is getting power and Ground (TEST 1 and TEST 2).
For our last test we're going to make sure that the MAF sensor is producing a Hertz signal that increases/decreases as you accelerate/decelerate the engine.
Remember, you'll need a multimeter that can read Hertz frequency. If you don't have one, check out my recomendations here: Buying A Digital Multimeter For Automotive Diagnostic Testing (at: easyautodiagnostics.com).
IMPORTANT: The MAF sensor must remain connected to its electrical connector for this test to work. You'll need to use a wire piercing probe or a back probe (on the connector) to be able to read the Hertz signal that the MAF sensor is producing. You can see an example of this tool here: Wire Piercing Probe.
CAUTION: The engine has to be running to perform the MAF sensor's Hertz signal test. Take all necessary safety precautions. Think safety all of the time!
These are the test steps:
- 1
With a suitable tool, connect to the red multimeter test lead to the wire labeled with the letter A as shown in the photo above.
- 2
Put the multimeter in frequency (Hz) mode.
- 3
Connect the black multimeter lead to the battery negative (-) terminal.
- 4
Start the already warmed up engine.
- 5
Note the Hertz reading on your multimeter as the engine idles.
This reading may be stable (with only small fluctuations) or unstable with very extreme fluctuations.
No matter what the instability in the reading, this will be your base reading. - 6
Manually accelerate the engine from the engine compartment as you watch the multimeter's frequency readings.
The Hertz frequency readings should increase as you accelerate the engine. - 7
Let go of the throttle and let the engine return to idle.
The Hertz reading should come down to the base Hertz reading you observed in step 5 of this test. - 8
Repeat steps 6 and 7 several times.
Your multimeter should register the Hertz reading increasing/decreasing as you accelerate/decelerate the engine.
Let's take a look at what your test results mean:
CASE 1: The Hertz values increased/decreased as you accelerated/decelerated the engine. This is the correct and expected test result and it let's you know that the MAF sensor is working correctly.
CASE 2: The Hertz values DID NOT increase/decrease as you accelerated/decelerated the engine. The MAF sensor is bad and needs to be replaced.
More 3.3L V6 Buick, Oldsmobile Tutorials
You can find a complete list of 3.3L Buick and Oldsmobile tutorials in this index:
Here's a small sample of the tutorials you'll find in the index:
- How To Test Engine Compression Test (3.3L V6 Buick, Oldsmobile).
- How To Test A Blown Head Gasket (3.3L V6 Buick, Oldsmobile).
- How To Test The Throttle Position Sensor (3.3L V6 Buick, Oldsmobile).
- What Does A MAF Sensor Do? (3.3L V6 Buick, Oldsmobile).
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