How to Clean the Mass Air-Flow (MAF) Sensor
2004-2009 Toyota Prius
Here's a simple maitenance item that can bring your MPG's back up slightly. If this sensor is too coated with carbon build up it won't function properly (lower MPG's) and needs a cleaning. All you need is a can of MAF cleaner and a few basic tools and you can DIY! This is more of a high mileage maintenance item but it never hurts to check and clean on lower mileage Prii. Oh yeah, and this is at least a $60 job at the dealer.
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Tools Needed:
- Small philips screwdriver or Flexible Socket Extension
Parts/Supplies Needed:
![](http://priusdiy.com/images/maint/maf01s.jpg)
1) Remove the engine air filter. MAF is highlighted in green above. Actually this is more of an optional step, you can start with step 2 if you don't need to inspect or replace the air filter. This is more for reference so you can see where it's located in the engine bay.
![](http://priusdiy.com/images/maint/maf02s.jpg)
2) Push on the tab indicted by the blue arrow while pulling out on the connector to release it.
![](http://priusdiy.com/images/maint/maf03s.jpg)
3) Use a small phillips screwdriver or flexible socket extension to remove the 2 screws circled in red. Make sure not to lose the screws into the engine void!
![](http://priusdiy.com/images/maint/maf04s.jpg)
Pictured is the MAF sensor removed along with the 2 screws. The flexible socket extension is also shown.
![](http://priusdiy.com/images/maint/maf05s.jpg)
Circled in red is one part of the actual sensor. As you can see it has a fair amount of carbon built up on it. It should be somewhat transparent.
![](http://priusdiy.com/images/maint/maf06s.jpg)
Here's the other part of the sensor that needs to be cleaned, these 2 wires. Tough to get a shot of this...
![](http://priusdiy.com/images/maint/maf07s.jpg)
4) Use your can of MAF cleaner to spray off the sensor and 2 wires (2 previous pictures) and then let it dry off on its own on some shop towels.
![](http://priusdiy.com/images/maint/maf08s.jpg)
5) Reinstall is reverse of removal. See how the sensor now has a shine to it? This = best MPG's.
Resources:
- 100k maintenance by Hobbit. Part of his 100k maitenance includes a MAF cleaning.
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