reset check engine light

Maybe the problem is not with the MAF sensor. Have you read the code?

 

if the code indeed was for a bad MAF SENSOR and you replaced it properly, the light should go off when you drive it. If it doesn't go off, that just means the code is probably not for the MAF sensor or the MAF sensor is not the correct one (not original part or incompatible).

 

Yes I think you should drive it for a couple days and see if it goes away. If it doesn't go away, you can go back to autozone and get the code read again. This time get the actual code and post it on here.

Many times auto parts stores will read the code and the people there don't really know what it's for. Then they go and sell you a part and send you on your way. It's the cheapest way to read the code, but you don't always get the correct interpretation of the code. That's why the dealer charges $150 to do what autozone did for free

 

So you really need to narrow down the issue, as that code can be related to a number of areas. Often these Toyota cars are very sensitive with their electronics, requiring Denso parts to work properly with their cars. If you got the sensor from Autozone, it may or may not work properly with your Prius.

If this were my car, I would first try an OEM original Denso/Toyota part before I look at anything else.

What repairs can fix the P0171 code?

1. Replacing the fuel pump.
2. Replacing the fuel filter.
3. Replacing the fuel pressure regulator.
4. Replacing the powertrain control module.
5. Replacing one or more injectors.
6. Replacing one or more oxygen sensors.
7. Replacing the mass air flow sensor.
8. Repairing a vacuum leak.

 

It's also always important to remember that the computers in the car are not clairvoyant.

If you get a code saying the engine is running too lean, all you know is that the computer thinks the engine is running too lean. The computer is not able to tell you why it's running too lean. It can only give a human that code, and hope the human will test the various possibilities.

Sure, the MAF sensor is one of the possibilities, but it could also be that the sensor is just fine and something else is causing the lean burn. Just automatically swapping the MAF sensor any time you get a code about it would be like just replacing your thermometer every time you have a fever.

The same is even true for other codes that have the name of some part in their one-liner descriptions. That still doesn't tell you it's that part that's bad. It's just a memory jog to get you thinking about everything potentially related to that part. The code is always giving you the question to start your diagnosis. It is never giving you the answer.