In this tutorial, I'm going to explain how to test the mass air flow (MAF) sensor using a multimeter. All the tests are explained in a step-by-step manner so you can easily find out if the MAF sensor is bad or not.
If you need to just clean the MAF sensor, you can find this article here: How To Clean The GM Mass Air Flow (MAF) Sensor (at: easyautodiagnostics.com).
NOTE: This is an ON CAR test -no need to remove the MAF sensor from its place to test it.
Contents of this tutorial:
- Common Symptoms Of A Bad MAF Sensor.
- What Tools Do I Need?
- Circuit Descriptions Of The MAF Sensor Connector.
- Where To Buy The MAF Sensor And Save.
- How Does The MAF Sensor Work?
- TEST 1: Making Sure The MAF Sensor Is Getting 12 Volts.
- TEST 2: Making Sure The MAF Sensor Is Getting Ground.
- TEST 3: Testing The MAF Signal With A Multimeter.
- More 3.4L V6 Buick, Oldsmobile Tutorials.
APPLIES TO: This tutorial applies to the following vehicles:
- 3.4L V6 Buick Rendezvous: 2002, 2003, 2004, 2005.
- 3.4L V6 Oldsmobile Alero: 1999, 2000, 2001, 2002, 2003, 2004.
- 3.4L V6 Oldsmobile Silhouette: 1996, 1997, 1998, 1999, 2000, 2001, 2002, 2003, 2004.
Other MAF sensor test tutorials (at: easyautodiagnostics.com):
- How To Test The GM MAF Sensor (3.1L, 3.4L, 4.3L, 5.0L And 5.7L)
- How To Test The MAF Sensor (GM 3.8L V6 1996-2005)
- How To Test The MAF Sensor (GM 4.8L, 5.3L, 6.0L, 8.1L)
- How To Test The GM MAF Sensor Express And Savana Van (2003-2008)
Common Symptoms Of A Bad MAF Sensor
The fuel injection computer relies heavily on the information that the mass air flow sensor provides. So when it fails, engine performance is going to suffer.
You're going to see one or more of the following symptoms:
- Check engine light illuminated on your instrument cluster by one of the following diagnostic trouble codes:
- P0101: MAF Sensor Performance Problem.
- P0102: MAF Sensor Circuit Low Frequency Signal.
- P0103: MAF Sensor Circuit High Frequency Signal.
- Lack of power when accelerating the engine/vehicle.
- Black smoke coming out of the tailpipe.
- Bad gas mileage.
- Engine idles rough.
- Engine starts but immediately stalls.
- Extended engine cranking. In other words, you've got to crank the engine a long time for it start.
You can find out more about the MAF sensor here: What Does The MAF Sensor Do? (3.4L V6 Buick, Oldsmobile).
What Tools Do I Need?
Thankfully, testing the mass air flow sensor doesn't require any expensive or exotic diagnostic test equipment.
Here's the list of tools that you'll need:
- A multimeter that can read Hertz frequency. If you don't have one and would like to buy one, check out my recommendations here: Buying A Digital Multimeter For Automotive Diagnostic Testing (at: easyautodiagnostics.com).
- A wire piercing probe or a back probe to be able to access the signal within the MAF sensor's output signal wire. To see what this tool looks like, click here: Wire Piercing Probe.
- Although not an absolute must, a code reader or a scan tool to be able to extract any codes registered in the fuel injection computer's memory.
As you can see, there's nothing in the list above that will break the bank!
Circuit Descriptions Of The MAF Sensor Connector
As you're probably already aware, the MAF sensor on your 3.4L Buick (Oldsmobile) has three wires sticking out of its connector. To be able to test the MAF sensor, we need to know what each wire does.
Here's a brief description of each:
| Terminal | Wire | Description |
|---|---|---|
| A | Yellow (YEL) | MAF Signal |
| B | Black with white stripe (BLK/WHT) or Black (BLK) | Ground |
| C | Pink with black stripe (PNK/BLK) or Pink (PNK) | 12 Volts DC |
To test the MAF signal circuit I recommend that you use a wire-piercing probe or a back probe. You can see what this tool looks like here: Wire Piercing Probe.
IMPORTANT: All of the tests are ON CAR TESTS, do not remove the mass air flow sensor from the vehicle or from its plumbing.
Where To Buy The MAF Sensor And Save
The following links will help you to comparison shop for a known automotive name-brand MAF sensor (no knock-offs) for your 3.4L V6 Buick or Oldsmobile vehicle:
How Does The MAF Sensor Work?
Here's a brief description of how the mass airflow sensor works:
- When you turn the key, 10 to 12 Volts are provided to the MAF sensor by the wire labeled with the letter C (see photo above).
- Ground is provided by the wire labeled with the letter B.
- Once the engine starts and air is flowing through the MAF sensor, the wire labeled with the letter A carries the frequency signal (that the MAF sensor creates) to the fuel injection computer.
- When engine RPMs increase, like when you step on the accelerator pedal, the MAF Hertz frequency signal increases.
- When you step off the accelerator pedal and engine RPM decreases, the MAF Hertz frequency signal decreases.
When the MAF sensor fails, it'll usually always stay stuck producing a single Hertz frequency value or none at all when engine RPMs increase or decrease.
You can find out more about the MAF sensor here: What Does The MAF Sensor Do? (3.4L V6 Buick, Oldsmobile).
