How To Test The MAF Sensor (2.5L Suzuki Grand Vitara)

TEST 2: Verifying The MAF Sensor Is Getting Power

Before we condemn the MAF sensor as bad (if it didn't pass TEST 1) we need to make sure that it's getting power. Power is in the form of battery voltage.

The wire that delivers power to the MAF sensor is the blue with black stripe (BLU/BLK) wire (of the MAF sensor engine wiring harness MAF sensor connector).

To check for this voltage, we'll do a simple multimeter voltage test. These are the steps:

NOTE: The connector in the illustration above is the connector on the MAF sensor itself and NOT the engine wiring harness MAF connector.

1. 1

   Disconnect the MAF sensor from its electrical connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

   Turn the key ON (but engine OFF).

4. 4

   Probe the BLU/BLK wire with the red multimeter test lead.
   
   NOTE: If you probe the front of the connector, be careful not to damage the female terminal. Use an appropriate tool (like a back-probe or a wire-piercing probe) to connect the multimeter test lead to the circuit.

5. 5

   Now connect the black multimeter test lead on the battery's negative (-) post.

6. 6

   Your multimeter should register 10 to 12 Volts DC.

Let's take a look at what your results mean:

CASE 1: The BLU/BLK wire, of the MAF sensor connector, has 10 to 12 Volts DC. This is the correct test result.

Now that you have confirmed that the MAF sensor is getting power, the next step is to check that it's getting Ground. Go to: TEST 3: Verifying The MAF Is Getting Ground.

CASE 2: The BLU/BLK wire, of the MAF sensor connector, DOES NOT have 10 to 12 Volts DC. This results lets you know that the MAF sensor is not bad, since without these 12 Volts DC, the MAF sensor can not function.

Although it's beyond the scope of this article to troubleshoot the cause of these missing 12 Volts, you have now eliminated the MAF sensor as bad. Resolving the issue that is keeping these 12 Volts from being supplied will solve the MAF sensor issue on your 2.5L Grand Vitara (or 2.5L Chevrolet Tracker).

TEST 3: Verifying The MAF Sensor Is Getting Ground

Up to this point, your tests have:

• Confirmed a MAF sensor code is lighting up the check engine light (P0101, P0102, or P0103).
• Confirmed that the MAF sensor's voltage signal is stuck in one voltage value (TEST 1).
• Confirmed the MAF sensor is getting power on the BLU/BLK wire.

Now you need to make sure that the gray with yellow stripe (GRY/YEL) wire of the MAF sensor electrical connector is feeding the MAF sensor with Ground.

Testing for Ground is done with another simple multimeter voltage test.

NOTE: The connector in the illustration above is the connector on the MAF sensor itself and NOT the engine wiring harness MAF connector.

IMPORTANT: Be careful that you don't intentionally or accidentally short the GRY/YEL wire to battery power or you'll fry your Suzuki Grand Vitara's PCM. Checking for Ground by doing a voltage test with a multimeter, as described in the test steps below, is a safe way to test this circuit.

These are the steps:

1. 1

   Disconnect the MAF sensor from its electrical connector.

2. 2

   Place your multimeter in Volts DC mode.

3. 3

   Turn the key ON (but engine OFF).

4. 4

   Probe the GRY/YEL wire with the black multimeter test lead.
   
   NOTE: If you probe the front of the connector, be careful not to damage the female terminal. Use an appropriate tool (like a back-probe or a wire-piercing probe) to connect the multimeter test lead to the circuit.

5. 5

   Now connect the red multimeter test lead on the battery's positive (+) post.

6. 6

   Your multimeter should register 10 to 12 Volts DC.

OK, let's take a look at what your results mean:

CASE 1: The multimeter confirms that the GRY/YEL wire is feeding Ground to the MAF sensor. This is the correct test result and confirms that the MAF sensor is bad and needs to be replaced.

Here's why: So far you verified:

• That the MAF sensor is not producing the correct signal voltage values when you accelerate/decelerate the engine (TEST 1).
• That it is being fed with power (TEST 2).
• That the MAF sensor does have a solid path to Ground (TEST 3).

These test results, interpreted together, indicate that the MAF sensor is bad.

CASE 2: The multimeter confirms that the GRY/YEL wire IS NOT feeding Ground to the MAF sensor. Double check your multimeter connections and repeat the test.

If your multimeter results still do not indicate 12 Volts, then the mass air flow (MAF) sensor is not fried and not the cause of the MAF sensor diagnostic trouble code (DTC) issue.

Here's why: Without a good path to Ground, that the PCM provides internally, the MAF sensor will not work. With this test result, you have eliminated the MAF sensor as bad.

MAF Sensor Code Keeps Coming Back

If you've already replaced the MAF sensor, on your 2.5L Grand Vitara (or 2.5L Chevrolet Tracker), with an after-market one, yet the MAF sensor problem and MAF trouble code keep coming back, then there's a good chance the MAF sensor you just bought is defective.

Wait, a new part not working? Yes, this is a widespread issue with these MAF sensors for this particular application, and it's something you should be aware of.

Most folks who had this experience fixed it by finding a used OEM Hitachi replacement at a junkyard or online. If you go the online route, eBay is your best bet.

On eBay, sellers sell the MAF sensor as a complete unit with the throttle body (usually $250 for the entire unit). So, you'll need to search for the 'throttle body assembly'.

If you buy the entire unit, you can then remove the MAF sensor and install it on your Grand Vitara.