Responsible for providing your Mazda ECU with the information it needs to properly operate your engine, the Mazda Protege MAF sensor can go bad over time. When this happens, you can use this handy How To guide to test your mass air flow sensor to see if it’s gone bad or needs replacing.
Using a hot wire filament inside of your mass air flow sensor, your Mazda can read the quantity of air that’s rushing into the engine. Using this information the ECU controls and orchestrates the engine’s fuel and ignition events.
Today I’ll be showing you how to test your Protege MAF in a 2000 Mazda ES with a 1.8 liter engine in it. The Protege MAF is located inline with your intake tract, and is mounted to the air filter box.
The Mazda Protege MAF is a three pin sensor that’s connected to your engine harness by way of a weather proof connector. Today you will be testing to make sure that your MAF is getting power, ground and sending the right signals.
Testing the Protege MAF for Power
Your mass air flow sensor has 3 total wires coming out of it. You will be using a multimeter to test the wires for power first and foremost. If you aren’t sure of what a multimeter is, or how to use one check our how to guide here.
To begin this MAF testing how to guide, you must first insert the Mazda ignition key and turn it to the “ON” position. This powers all the sensors in your engine bay, and will allow you to check whether or not your MAF is getting power.
Now unplug your Protege MAF and the first wire you will be testing is PIN C, which should be a WHITE wire with a RED stripe. Gently probe the front of PIN C with the red lead of your multimeter, and touch the black lead to the negative terminal of your battery.
With the key turned to the “ON” position, you should see 12 volts at this wire. Now the next thing you will be testing on the Protege MAF, check PIN A for a low reference ground signal. If you have a ground signal here at PIN A, your Protege MAF has the right power and ground to operate.
The final part of this how to test a Protege MAF guide is to measure the signal, which is PIN B. This signal wire is what transmits the data back to your Mazda ECU, which allows it to run the engine.
How does the Protege MAF work?
The Protege MAF uses a hot wire element, that lowers in voltage as air rushes through it. This causes changes and fluctuations in the output voltage, and this is what you ECU uses to interpret air flow.
In order to complete this part of our Protege MAF test, you must use a paperclip to backpin that middle PIN. Reconnect the MAF connector and slide the paper clip into PIN B, and this next part is a little more dangerous. Keep all your clothing and personal items clear of your drive belts and engine, and turn on your engine.
Next you will be measuring the middle pin for Voltage using your multimeter. As I explained earlier, the more air that rushes into the engine, the higher the voltage from the Protege MAF will be.
Once you have your engine started, the Protege MAF output should be around 1.1 volts DC. Now have a friend raise the engine speed to 1500 RPM, and the signal should rise to 1.7 volts DC. The final RPM check would be to raise the engine speed to 3000 RPM, and around this RPM your MAF output should be 1.6-1.7 volts DC.
If the test results don’t match our How To test your Mazda Protege MAF, it means your mass air flow sensor has failed and needs replacing. Check our online store for a re-manufactured unit or head to your local auto parts store. Have any questions about our how to guide? leave us a comment below and let us know!