TEST 2: Verifying The MAF Sensor Is Getting Power
To be absolutely sure that the MAF sensor is bad (if it did not pass TEST 1), we need to make sure it's getting power and Ground.
In this test section we're gonna' check that the MAF sensor is getting power (which is in the form of battery voltage).
The pink with black stripe (PNK/BLK) wire, of the MAF sensor connector, is the one tasked with supplying power to the MAF sensor.
To check for this voltage, we'll do a simple multimeter voltage test. These are the steps:
With your multimeter still in Volts DC mode from the previous test and the key on (but engine off).
Probe the PNK/BLK) wire of the MAF sensor connector. This is the wire that connects to MAF sensor pin A in the illustration above.
You can test for these 12 Volts with the MAF sensor's electrical connector connected to the MAF sensor or not, just avoid probing the front of the connector.
Now Ground the black multimeter test lead on the battery's negative post.
If the PNK/BLK wire has power, your multimeter will register 10 to 12 Volts DC.
Let's take a look at what your results mean:
CASE 1: The PNK/BLK wire, of the MAF sensor connector, has 10 to 12 Volts DC: This is the correct result and it's starting to look like the MAF sensor is bad but you still need to check that the MAF sensor is getting Ground. For the Ground test, go to: TEST 3: Verifying The MAF Is Getting Ground.
CASE 2: The PNK/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 Suzuki Verona.
TEST 3: Verifying The MAF Sensor Is Getting Ground
If you've reached this point, you have checked and confirmed:
- A MAF sensor trouble code is lighting up the check engine light (P0101, P0102, or P0103).
- The MAF sensor's voltage signal is stuck in one voltage value (TEST 1).
- The PNK/BLK wire of the MAF sensor connector is feeding battery power to the sensor.
We're now gonna' make sure that the MAF sensor has Ground. This Ground is fed to the MAF sensor by the light green with black stripe (LT GRN/BLK) wire of the MAF sensor electrical connector.
Testing for Ground is done with another simple multimeter voltage test.
IMPORTANT: Be careful that you don't intentionally or accidentally short the LT GRN/BLK wire to battery power or you'll fry your Suzuki Verona'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:
With your multimeter still in Volts DC mode from the previous test and the Key On (but engine Off).
Probe the LT GRN/BLK wire with the black multimeter test lead.
NOTE: It doesn't matter if you probe this circuit (wire) with the connector connected to the MAF sensor or not, but do not probe the front of the connector (if you decide to unplug the connector to test for this path to Ground).
Now connect the red multimeter test lead on the battery's positive (+) Post.
If the LT GRN/BLK wire has Ground, then your multimeter will register 10 to 12 Volts DC.
OK, let's take a look at what your results mean:
CASE 1: The multimeter confirms that the LT GRN/BLK wire is feeding Ground to the MAF sensor: This is the normal result and it means that the mass air flow (MAF) sensor on your Suzuki Verona is fried and needs to be replaced.
Here's why: In MAF sensor TEST 1 and 2, you verified that the MAF sensor is not producing the correct values (when you revved the engine up/down) and that it does have power. In this test step you have confirmed that the MAF sensor does have a solid path to Ground, these results, interpreted together, indicate that the MAF sensor is bad.
CASE 2: The multimeter confirms that the LT GRN/BLK 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.