TEST 1: Making Sure The MAF Sensor Is Getting 12 Volts
The very first thing that we're gonna' do, is to find out if the mass air flow sensor is receiving 10 to 12 Volts.
The wire that feeds 12 Volts to the mass air flow sensor is the white with red stripe (WHT/RED) wire of the sensor's 3-wire connector.
To check for the presence of these 12 Volts, we're gonna' do a simple multimeter test on the wire.
In the photo above, I've labeled the WHT/RED wire with the number 1.
OK, let's get testing:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the MAF sensor from its electrical connector.
- 3
Connect the black multimeter test lead directly on the battery negative (-) terminal.
- 4
With red multimeter test lead, gently probe the female terminal that connects to the wire labeled with the number 1 in the photo above.
This is the WHT/RED wire of the MAF sensor connector. - 5
Turn the key to the ON position (RUN position).
- 6
Your multimeter should register 10 to 12 Volts DC.
Let's examine your test result:
CASE 1: The multimeter registered 10 to 12 Volts DC. This is the correct test result and it tells you that your Mazda's mass air flow (MAF) sensor is getting power.
The next step is to make sure that the MAF sensor is getting Ground. For this test, go to: TEST 2: Making Sure The MAF Sensor Is Getting Ground.
CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. Make sure that you're testing the correct wire, that your connections are OK, and repeat the test.
If your multimeter still doesn't register between 10 to 12 Volts, then you've found a problem that needs to be corrected. Without these 10 to 12 Volts, your Mazda's MAF sensor won't work.
The following MAF sensor circuit diagram will help you further troubleshoot this problem: MAF Sensor Circuit Wiring Diagram (1996-1998 1.5L Mazda Protege).
TEST 2: Making Sure The MAF Sensor Is Getting Ground
For our second test, we're gonna' make sure that the mass air flow sensor is receiving Ground.
The wire that supplies Ground to the MAF sensor is the black with light green stripe (BLK/LT GRN) wire of the sensor's 3-wire connector.
In the photo above, the BLK/LT GRN wire is labeled with the number 3.
OK, these are the test steps:
- 1
Place your multimeter in Volts DC mode.
- 2
Disconnect the MAF sensor from its electrical connector.
- 3
Connect the red multimeter test lead directly on the battery positive (+) terminal.
- 4
With black multimeter test lead, gently probe the female terminal that connects to the wire labeled with the number 3 in the photo above.
This is the BLK/LT GRN wire of the MAF sensor connector. - 5
Your multimeter should immediately register 10 to 12 Volts DC.
NOTE: This is Ground is a chassis Ground and is available at all times (with or without turning the key to the RUN position)
Let's interpret your test results:
CASE 1: The multimeter registered 10 to 12 Volts DC. This is the correct and expected test result. It confirms that the MAF sensor is getting Ground.
For the last test, go to: TEST 3: Checking The MAF Sensor Signal With A Multimeter.
CASE 2: The multimeter DID NOT register 10 to 12 Volts DC. Make sure that you're testing the correct wire, that your connections are OK, and repeat the test.
If your multimeter still doesn't register voltage, then you've found a problem that needs to be corrected. Without this Ground, your Mazda's MAF sensor won't function.
The following MAF sensor circuit diagram will help you further troubleshoot this problem: MAF Sensor Circuit Wiring Diagram (1996-1998 1.5L Mazda Protege).
Repairing this Ground issue will get the MAF sensor back on its feet.
