TEST 1: Making Sure The MAF Sensor Is Getting 12 Volts
For our first test we're going to make sure that the MAF sensor is getting 10 to 12 Volts DC.
The wire that delivers these 10 to 12 Volts to the MAF sensor is the wire labeled with the letter C. This is the pink (PNK) wire in the photo above.
If power is available to the MAF sensor, then our next step is to make sure that it's getting Ground (TEST 2).
Let's get started:
- 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 make sure that the wire labeled with the letter B is delivering Ground. 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
In this section we're going to make sure that the MAF sensor is getting Ground.
Ground is fed to the sensor via the wire labeled with the letter B in the photo above.
Depending on your particular 3.4L V6 Buick or Oldsmobile, the Ground wire will either be a black (BLK) wire or a black with white stripe (BLK/WHT) wire.
If your test results confirm that Ground is being supplied to the MAF sensor, then your next step is to check the output signal of the MAF sensor itself (TEST 3).
Alright, 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 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
So far, the previous two tests have confirmed that the MAF sensor is receiving power and Ground.
Now we're going to test the output signal of the mass air flow sensor.
This signal is a Hertz frequency signal. As such you'll need to use a multimeter that can read Hertz frequency to verify this signal.
Remember, you'll need a multimeter that can read Hertz frequency. If you don't have one, check out my recommendations 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 3.4L V6 Buick, Oldsmobile Tutorials
You can find a complete list of 3.4L V6 Buick (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 (3.4L V6 Buick, Oldsmobile).
- How To Test A Blown Head Gasket (3.4L V6 Buick, Oldsmobile).
- What Does The CKP Sensor Do? (3.4L V6 Buick, Oldsmobile).
- How To Test The Throttle Position Sensor (3.4L V6 Buick, Oldsmobile).
If this info saved the day, buy me a beer!
