HI Everyone,

Last weekend I got the dreaded "Malfunction Indicator" Ran the code ( P0101) which indicates an issue with the Mass Air Flow Sensor. Ok, no biggie, could be as simple as a sensor cleaning. I read online that K&N air filters may cause the sensors to accumulate dust/debris and figure that's probably the reason. As I had no issues with fuel economy, starting stopping, accelerating, I reset the code and continued on my way ( I drive <200km a month and figured I could clean this when it was not as cold outside).

This morning the Malfunction Light flashed back on again. I noted on the road that I could not accelerate in the typical nfiniti fashion. I would depress the gas and it would not respond. The RPM's didn't move then shot to 5-6K with about a 5km acceleration. Low speed/RPM's are just fine so figured that the sensors are not doing their job. Time to clean...

There are two screws on each sensor (and two sensors). I can only remove one screw from each side and for the life of me cannot get the other screws off...they are starting to strip on the on inside. It's bad enough that I have to clean two sensors, but when I cannot the screws off even one side, it's frustrating!

Has anyone cleaned/replaced their MAF's? If so, is there a trick to getting the screws out? It's just a Phillips head screw so I don't think I should be having this much difficulty.

Thanks for any advice!

Lapin wrote:
is there a trick to getting the screws out? It's just a Phillips head screw so I don't think I should be having this much difficulty.

Maybe there is loctite on the screws? maybe try holding the tip of a soldering iron on the screws for a minute or two, if there is loctite on the screws it should melt it allowing the screws to turn.

I've never removed a MAF sensor from an EX35... but I have fixed a P0101 problem on another vehicle of mine.

Be sure to use a Magnifying Glass to look at the little tiny sensors within the MAF unit, to ensure they are clean.

I sprayed mine using MAF Sensor cleaner... and the code re-appeared... after the code had been originally cleared the first time.

So using a Magnifying Glass... I used an old toothbrush to delicately clean the microscopic sensors... and since then, the P0101 code has not re-appeared.

Some might say not to do this... but I was getting the codes anyways and it wasn't going away... so my MAF Sensor was basically screwed... and if I buggered it up using the toothbrush, then oh well... I had to buy a new one anyways. I had nothing to lose.

Thanks everyone for the feedback. Turns out (in proper light) that the screw is also a nut (7mm) and can be removed that way (just don't drop the wrench into the engine bay like I did!) Managed to remove both sensors and while they appeared to look clean, I gave them a good spray and allowed to dry. put them back in and reset the code. She is purring like a kitten and I think even better than I have ever experienced in the 1.5 years I have owned the vehicle. I had no idea that MAF's should be cleaned every time you change your oil. We'll see if my fuel efficiency improves in the next few months...

How did you clean it... and what did you use?

This is what my GM MAF Sensor looked like...

EXceptional wrote:How did you clean it... and what did you use?

EXceptional: I picked this up from Canadian Tire and followed the instructions: 10-15 sprays on the entire sensor and allowed to fully dry on a shop towel. Made sure to spray directly on the hot wires as well. I put each into a ziplock snack bag when I transported them back to my car ( I live in a condo building with an underground parkade). It's critical that these remain as clean as possible when inserting them back in.

http://www.canadiantire.ca/en/pdp/crc-s ... p.html#srp

Lapin wrote:

EXceptional wrote:How did you clean it... and what did you use?

Ah, you took off the throttle body as well, I removed the senor directly from top. Here is what I cleaned:

Is it good to clean the MAF sensors even though there is no code showing? I doubt if it was cleaned before I bought a car.

If the sensor is dirty or not working properly it is possible it may be over reporting the amount of air entering the engine which in turn will cause extra fuel than normal to be added to the air fuel mixture before combustion in the motor. This will result in wasted gas and lower gas mileage.

Most modern day mass air flow sensors work by applying a current through a set of electrical filament wires. As air passes over the wires, the wires cool down, decreasing the resistance of the system. More current is then passed through the wire to heat it back up and obtain an equilibrium resistance value. The amount of current needed to heat the wire up is recorded and used to back calculate the air flow rate through the device.

Thus having a properly functioning Mass Air Flow Sensor is critical to the proper functioning of your fuel injection system and as a result fuel economy. If a MAF sensor is malfunctioning badly beyond a certain threshold it will cause the computer to display an error code that may alert you to a malfunctioning MAF. However, if the sensor’s elements are just dirty then it will be constantly misreading your air ratio and possibly causing lower gas mileage.

Luckily there is an easy way to do basic cleaning maintenance on your MAF sensor if your vehicle has over 60,000 miles on it. Once the sensor is removed from the vehicle use a common electrical connector cleaner spray and spray the wire filaments of the mass air flow sensor several times. Let the unit dry and repeat the process several more times to make sure that all carbon deposits or grime has been removed from the wire filaments. Just make sure not to touch or hit the wires. Touching the wires can put your finger’s oil on them causing improper readings. Once the sensor is dry and cleaned to your specifications reinstall it back in your vehicle.

[copy and paste from http://www.mpgenhance.com]

Lapin wrote:Ah, you took off the throttle body as well, I removed the senor directly from top. Here is what I cleaned.

My photo was of the MAF sensor only, which was removed from a 2003 GMC truck. The throttle body in this truck, is located about 15 inches away, bolted on to the engine.

Thank you for the detail explanation EXceptional, Im assuming in my case, if the throttle body was really dirty that the MAF is as well and I might clean it up. Probably I'll do ti on the weekend.

I have also come across this video on yt, how to clean MAF sensor
ChrisFix guy is really good in explaining all kinds of fixes on a cars. I've been following him for a while now and picked up a lot info about cars what I didn't know before.

Well that was short-lived. My second time driving I'm experiencing the same issue. Poor acceleration and I have to hammer on the gas pedal to make it crawl 5km/hour more when I'm at 80km/hour. RPMs will not rise above 2K and then will suddenly jump to 5-6K. Bah. Guess I will have to test to see which MAF is faulty and replace.

Is there any chance it could be anything other than the MAF that is causing this acceleration issue? The code is also pulling for the MAP (but I think that is due to the fact the MAF is faulty and compensating to a certain extent). Perhaps O2 Sensors?

Thanks for any thoughts/feedback!

There are really good video's on how to determine if your O2 sensors are working and if your Catalytic Convertor is plugged.

Using a OBD Scan Tool, your front O2 sensor numbers should be fluctuating wildly as the car's computer is analyzing the garbage in the exhaust... and your rear O2 sensor should be fluctuating, but more calmly like... because its measuring what the Catalytic Convertor is processing, which should be a good exhaust product because that's what the guts of the Catalytic Convertor does to the junk that's in the exhaust emissions.

Then you could take a laser temperature probe and see what the Catalytic Convertor exhaust pipe intake temperature is, versus the Catalytic Convertor exhaust pipe output temperature, both readings taken pointing the laser right at the exhaust pipe metal. The output temperature should be much hotter than the input temperature into it. This means that the contents of the Catalytic Convertor isn't plugged and the exhaust is flowing through and the Catalytic Convertor is doing its job super-cooking all the bad stuff in the exhaust emissions.

I'm not a mechanic, but I'm learning... so if I have screwed up somewhere in the text of this reply... keep in mind... it is the good ol internet, isn't it? Do your research. I learned all the above on YouTube.

Also, if you just sprayed your hot wires on the MAF Sensor, it could still be dirty. I used long Q-Tips and a Magnifying Glass to very carefully clean the hot wires.

I've watched a lot of Chris-Fix's videos... they are well done.

eXceptional: Thanks for the tips. Full disclosure: This is my first car and I have zero car mechanical experience. All of my learnings have come from the internet/you tube (and this forum of course!)

I am going to try cleaning the senors again today with your suggestions. I just ordered a multimeter and will test each sensor this weekend to determine if anything is faulty or if it's not pulling any resistance. Hope I don't zap myself or the car. Pending that outcome, I'll check the MAP (if I can locate it..suggestions welcome on where it is housed)and vacuum hose for leaks. If that doesn't yield any results, I'll have to take it in to Infiniti. They have been good to me there and if I present the problem and my troubleshooting, perhaps they can refrain from fully screwing me over.

Seems that the problem is either the MAF or the MAP according to the code...

Cleaned the sensors again as per eXceptional's advice and cleared the code. Also located the MAP's and they appear to be free of leaks and are fluctuating with RPMs. Curious to know why each MAF has different color wires...I would assume they would have the same color wires on each engine bank? Will test resistance on each one if I can figure out the which is the IAT and the ground No black wires on the right engine bank! If someone can refer me to the appropriate section of the Service Manual, that would be appreciated. Also, would it be necessary to change both MAFs?