Dear Car Talk:
If you change the mass air flow sensor, do you need to do anything else, or are you good to go? — Leslie
Generally, you should be good to go, Leslie.
Newer cars need to have sensors paired to the car’s computer, so they can speak to each other. But for older cars, it’s pretty much plug and drive.
I’m going to guess that your “Check Engine” light came on, Leslie. So, you went to a local auto parts store that offers free scans, right?
They plugged in their scanner, read the error code and told you that you needed a mass air flow sensor. That seems reasonable, particularly if your car is an older one.
The mass air flow sensor reads the mass — or density — of the air that’s coming into the engine. Based on that reading, the computer then knows how much gasoline to send into the cylinders, to get the fuel-air mixture right.
If the sensor stops working, the car may run poorly, or it may run rich and overwhelm your catalytic converter (which costs many times more than the sensor). Now, I’m guessing that the guys who did the scan also want to sell you a new mass air flow sensor. And, you’re wondering if you can replace it yourself. The answer is probably “yes.”
Provided you have the wherewithal to locate it in the engine compartment, you simply unplug the old one, plug in the new one, rotate the fuzzy dice and drive away. But, if it’s a newer car, and the “Check Engine” light stays on after you plug in the new part, you’ll need to visit a mechanic, who can use his scan tool to introduce the new sensor to the computer.
That’s the polite thing to do, Leslie.
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