Originally Posted by SonicVQ

The second sensor is the absolute pressure sensor for the brake booster.

When the VVEL is controlling the air intake to the engine, the intake manifold vacuum is very low, about 80 KPa / 4 inHg
There is a one way valve in the line from the intake manifold to the brake booster.
This sensor monitors how much brake booster vacuum there is, and when it gets low, the ECU will close/open the throttle bodies to increase the booster vacuum.
Cool huh?

Originally Posted by SonicVQ

Brake Booster Pressure Sensor:

Originally Posted by Michael Moheban

Good Evening Everybody,




Id like to preface this by saying this method only works if the fault code was caused by a dirty MAP sensor. This method works just as well for both MAF sensors if they caused the fault (MAF = P0101). This method will not work if your MAP sensor is physically broken.




Ok so my 2011 Infiniti G37x preforms beautifully; always smooth, and sharp. Every few months however, the MAP sensor triggers a fault code. So how do we fix this?




You're going to want to grab a flat head screwdriver from your toolbox and tighten the screw clamps around the intake piping. One reason the MAP sensor faulted could be a leak in your vacuum intake lines. Any leaks can cause pressure discrepancies within the engine, which screws with your MAP sensor. You're going to want to visually inspect them for cracks, breaks, deformations, and holes. If it passes your visual inspection to your satisfaction it's time to take the engine cover off to get to the MAP sensor, which is located on far right corner of the top portion of the engine block. If you're having trouble finding your MAP sensor, click here to view a google images search of the MAP's location.




Now remove the screw holding the MAP sensor to the engine, for this you'll need a 10mm socket wrench. With some MAF/MAP sensor cleaner spray the inside of the sensor 8-10 times, making sure to flip the sensor upside down to allow for the fluid to drain. After your done spraying the sensor, put the Engine cover back your car, and let the sensor sit for 15-20 minutes under room temperature conditions, to allow the cleaning solvent to evaporate. It also doesn't hurt to give the electrical connection a squick spray or 2, to clean it out. A good way to tell if your sensor is free from any cleaning solvent is to give it a small (I mean very small) sniff. The cleaner is made from non-polar organic volatile substances, so I recommend caution, and gloves, when you're using the stuff. Once you're sure your sensor is free of any residual solvent, put the sensor back, and secure it with its screw. Once this is done you can plug the sensor cable into the sensor. It doesn't really matter if you plug it in before you screw it down, I just find it easier to use the socket wrench without the wiring there. Now you're all set to put the engine cover back on.




Once the engine cover is back on, we need to reset the ECU BEFORE you turn the car on. I find it easiest to follow along with this video, which always works for me. I find it best to follow along exactly what he's doing as he's doing it in the video. It might take 1 or 2 tries but you'll get it.




Once you do this you're all set to turn your car on! I usually let it idle for 20 minutes, so the ECU can get new data for the cleaned sensor. At this point, if the only issue was the dirty sensor, you should NOT see the Service Engine Soon light come on. If the sensor is malfunctioning, the ECU will recognize this during the idle period, and you should get the same fault code. This means the sensor needs to be replaced. OEM sensors have never steered me wrong, but can be on the expensive side. The Hitachi MAP sensor is a decent choice, although less reliable, it is much more affordable at around half the price (~$105) compared to OEM (from Infiniti, ~$235).




Also, feel free to recommend better ways of doing this, as well as advice. I'm a chemist, not a mechanic but this has always worked for me. Best of Luck!




-M




Edit 1: Grammar/Spelling; DO NOT SPRAY THE ENGINE BLOCK WITH MAP/MAF SENSOR CLEANER, ONLY SPRAY THE SENSOR AWAY FROM THE ENGINE

Originally Posted by D.Song

THANK YOU SO MUCH FOR THIS!!!

I cleaned my MAP Sensor, and reset the ECU but still had the Service Engine Light come on. Then I read your post more closely and tightened the vacuum intake lines like you mentioned (which were very loose) and reset the ECU, and VOILA!! All fixed!!

You saved me a pretty penny, thank you for this post sir 🫡

Originally Posted by Jrentas

Dumb question but your vacuum intake lines, which ones are they? I want to make sure I tighten mine I’m having this problem now.

Originally Posted by abrecos

It's any rubber hoses that attached to your intake plenum, including PCV valves and hoses that connects your intake to valves body.

Originally Posted by Michael Moheban

Good Evening Everybody,




Id like to preface this by saying this method only works if the fault code was caused by a dirty MAP sensor. This method works just as well for both MAF sensors if they caused the fault (MAF = P0101). This method will not work if your MAP sensor is physically broken.




Ok so my 2011 Infiniti G37x preforms beautifully; always smooth, and sharp. Every few months however, the MAP sensor triggers a fault code. So how do we fix this?




You're going to want to grab a flat head screwdriver from your toolbox and tighten the screw clamps around the intake piping. One reason the MAP sensor faulted could be a leak in your vacuum intake lines. Any leaks can cause pressure discrepancies within the engine, which screws with your MAP sensor. You're going to want to visually inspect them for cracks, breaks, deformations, and holes. If it passes your visual inspection to your satisfaction it's time to take the engine cover off to get to the MAP sensor, which is located on far right corner of the top portion of the engine block. If you're having trouble finding your MAP sensor, click here to view a google images search of the MAP's location.




Now remove the screw holding the MAP sensor to the engine, for this you'll need a 10mm socket wrench. With some MAF/MAP sensor cleaner spray the inside of the sensor 8-10 times, making sure to flip the sensor upside down to allow for the fluid to drain. After your done spraying the sensor, put the Engine cover back your car, and let the sensor sit for 15-20 minutes under room temperature conditions, to allow the cleaning solvent to evaporate. It also doesn't hurt to give the electrical connection a squick spray or 2, to clean it out. A good way to tell if your sensor is free from any cleaning solvent is to give it a small (I mean very small) sniff. The cleaner is made from non-polar organic volatile substances, so I recommend caution, and gloves, when you're using the stuff. Once you're sure your sensor is free of any residual solvent, put the sensor back, and secure it with its screw. Once this is done you can plug the sensor cable into the sensor. It doesn't really matter if you plug it in before you screw it down, I just find it easier to use the socket wrench without the wiring there. Now you're all set to put the engine cover back on.




Once the engine cover is back on, we need to reset the ECU BEFORE you turn the car on. I find it easiest to follow along with this video, which always works for me. I find it best to follow along exactly what he's doing as he's doing it in the video. It might take 1 or 2 tries but you'll get it.




Once you do this you're all set to turn your car on! I usually let it idle for 20 minutes, so the ECU can get new data for the cleaned sensor. At this point, if the only issue was the dirty sensor, you should NOT see the Service Engine Soon light come on. If the sensor is malfunctioning, the ECU will recognize this during the idle period, and you should get the same fault code. This means the sensor needs to be replaced. OEM sensors have never steered me wrong, but can be on the expensive side. The Hitachi MAP sensor is a decent choice, although less reliable, it is much more affordable at around half the price (~$105) compared to OEM (from Infiniti, ~$235).




Also, feel free to recommend better ways of doing this, as well as advice. I'm a chemist, not a mechanic but this has always worked for me. Best of Luck!




-M




Edit 1: Grammar/Spelling; DO NOT SPRAY THE ENGINE BLOCK WITH MAP/MAF SENSOR CLEANER, ONLY SPRAY THE SENSOR AWAY FROM THE ENGINE