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Mass Air Flow Sensor Replacement
 
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Pelican Technical Article:

Mass Air Flow Sensor Replacement

Jared Fenton

Time:

1 hour1 hr

Tab:

$400

Talent:

*

Tools:

Flat head screwdriver

Applicable Models:

Porsche 955 Cayenne (2004-10)
Porsche 955 Cayenne GTS (2008-10)
Porsche 955 Cayenne S (2003-10)
Porsche 955 Cayenne Turbo (2003-10)
Porsche 955 Cayenne Turbo S (2006-10)

Parts Required:

New MAF sensor

Hot Tip:

Sometimes, old MAFs can be cleaned

Performance Gain:

Smoother running engine, better MPG

Complementary Modification:

Clean throttle body

The mass airflow sensor (MAF) is used to measure the amount and temperature of air that is entering the engine at any given time. The mass airflow sensor senses the total amount of air passing the sensor and allows the fuel injection system to adjust the fuel mixture to compensate for cold weather and/or high altitude conditions.

The first indicator that you may have a problem with the MAF is the presence of a check engine light (CEL) on your dashboard. The CEL can be caused by a wide variety of problems: you need to read the diagnostic trouble codes (DTC) from the computer to get a starting clue as to what the problem is. Sometimes, there is no change in how the engine is running. Other times, you might experience a loss in power, sluggish running and a decrease in gas mileage as a result.

The computer will know if something is wrong with the MAF because it will compare the values being output by the sensor to "expected" values that it should be receiving. This common-sense check by the computer helps to diagnose problems with every component in the system. If the MAF becomes dirty and is falsely indicating to the engine that the car is receiving very little air while at full throttle, then the computer will most likely trigger a DTC and light up the CEL on your dash.

To read the DTC, you'll need to access the on board diagnostic (OBD) connector under the dashboard. Through this connector, a computer is able to retrieve the codes using a diagnostic software package. Products such as Durametric are invaluable for this and other diagnostic tasks. However, for those of you on a budget, many auto parts stores have a generic hand held scanner that can retrieve codes. Usually for free as well. In this case, simply write down the DTC and look it up online.

Typically, there are three DTCs that indicate a direct problem with the MAF: P0101: Mass Air Flow Sensor: Signal Implausible; P0102: Mass Air Flow Sensor: Below Limit; P0102: Mass Air Flow Sensor: Above Limit

Vacuum leaks and other air leaks in the system can also cause MAF sensor errors. If you have a crack or leak in your air intake downstream of the sensor, then the MAF will be sensing less air than the engine is actually receiving. Always check the intake system for leaks. Many times, I've encountered poor running engines that ran smooth once a hose clamp was tightened.

Cleaning the MAF involves removing the actual sensor from the mounting tube. To do this, you'll need a tamper-proof T20 Torx driver. Once free, use a can of MAF sensor cleaner (available at any auto parts store) to spray off the hooked end of the sensor. Follow the directions on the side of the can for best results. NOTE: Late model vehicles may have a hot wire style sensor. Newer model vehicles have a hot film style sensor. WARNING: If your MAF sensor is made of film, it is NOT possible to clean it. You will need to replace it!

After you have replaced or cleaned the sensor and cleared the DTC with a scanner, you need to go drive the car and see if the code returns (usually around 10-20 miles). If the same error code appears, then the problem probably lies elsewhere. Most of the time when you have an error code indicating a problem with the mass air flow sensor, it is usually solved by the installation of a new sensor. However, the computer can become confused sometimes and give misleading error messages. Wire harness issues, DME problems, and vacuum leaks may all give false MAF error codes. At this point, it's best to dive into the factory manuals and start going through the laborious test procedures contained in there.

Shown here is one of the two MAF sensors on your Porsche Cayenne (green arrow).
Figure 1

Shown here is one of the two MAF sensors on your Porsche Cayenne (green arrow). Replacement of the sensor is a very easy job, taking less than one hour with only a flat head screwdriver.

Use a flat head screwdriver to pry up the wire clip on each MAF sensor housing.
Figure 2

Use a flat head screwdriver to pry up the wire clip on each MAF sensor housing.

On each side of the car, loosen the hose clamps holding the plastic boot to the intake plenum and the MAF sensor (green arrows).
Figure 3

On each side of the car, loosen the hose clamps holding the plastic boot to the intake plenum and the MAF sensor (green arrows). Slide the boot back and over the plenum. Once clear of the plenum, pull the boot off the end of the MAF sensor housing.

Press the tab on the electrical connector going to the MAF (green arrow) and pull it off.
Figure 4

Press the tab on the electrical connector going to the MAF (green arrow) and pull it off. Sometimes these connectors can stick a bit and need a tiny bit of force to free them up.

Now remove the MAF sensor housing from the car.
Figure 5

Now remove the MAF sensor housing from the car.

Carefully inspect each intake boot for cracks or tearing.
Figure 6

Carefully inspect each intake boot for cracks or tearing. If you see any, replace the boot.

Shown here is the business end of the MAF sensor.
Figure 7

Shown here is the business end of the MAF sensor. The plastic grid backed with a thin mesh screen prevents damage to the sensor from any possible debris in the intake tract.

To remove the MAF from the housing, use a tamper-proof T20 Torx driver (green arrows) to remove the screws and pull the MAF sensor up and out of the housing.
Figure 8

To remove the MAF from the housing, use a tamper-proof T20 Torx driver (green arrows) to remove the screws and pull the MAF sensor up and out of the housing.

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Comments and Suggestions:
Sakheramamreh@hotmail.com Comments: P 0102 that's which side of the sensor they mean driver side or passenger side to I can change it
October 20, 2016
  Followup from the Pelican Staff: It's the mass air flow sensor. Should only be one. - Nick at Pelican Parts  
Sakher Comments: I was having code p 0102 and I change 2 sensor side but I drive the car after that the check engin come back after 5 miles
Do you know why
October 19, 2016
  Followup from the Pelican Staff: The air duct could have a leak or the wiring to the sensor may be faulty. - Nick at Pelican Parts  
Osama Comments: I have Cayenne V6, the fuel consumption is around 23Liter/100KM, could this be because of the MAF although no error code is there.
May 4, 2016
  Followup from the Pelican Staff: hard to say. What are the fuel trim numbers? Check at idle, 2500 rpm no load oin Park, and a steady cruise at 2500 rpm. - Nick at Pelican Parts  
Mich Comments: I cleared the codes then next morn got a P1175 which I assume is bank 2 so I replaced bank 2 MAF and reset the code will see what happens next. Funny thing is my Cayenne S has a MAF #0281002435 the replacement was #95560612331 both appear to be compatible with 2005 Cayenne S I thought the 435 was a turbo MAF.
March 23, 2016
  Followup from the Pelican Staff: You may have purchased one without a air temp sensor in the right location.


I’m not the best with part numbers.

Give our parts specialists a call at 1-888-280-7799. They can figure out what part or repair kit you need.
- Nick at Pelican Parts
 
Mich Comments: I replaced both mafs on a 05S yesterday and after a driving it a while I got a P0112 - Intake Air Temperature Circuit Low Input. Does that mean 1 or both of the mafs are bad? Car drives normal. Before this my engine was cutting in and out upon acceleration or while driving. Was told it was mafs by dealer but did repair myself.
March 20, 2016
  Followup from the Pelican Staff: Confirm the sensors are both correct, the part numbers match for your vehicle. Then check the IAT signal to the DME. The wiring may be damaged. - Nick at Pelican Parts  
Grant Comments: Could a faulty MAF cause the engine management system to "turn off" the turbo? I have a 2007 Cayene turbo and the turbo is not kicking in but I have no other problems with the car, it is running well . There has been no engine warning light.
February 14, 2016
  Followup from the Pelican Staff: I would assume it would reduce engine power due to a default airflow map. But the turbocharger should still function. - Nick at Pelican Parts  
Junior Comments: I have a 2004 Cayenne Turbo. I am not able to remove the electrical connectors to the MAF Sensor. I don't want to force it and end up breaking them. Are there tricks on removing these?
January 19, 2016
  Followup from the Pelican Staff: Can you share a photo of the connector? There should be a retaining tab under the connector that has to be released. - Nick at Pelican Parts  
AngiePat Comments: Hi
I am trying to remove my mass air flow for cleaning using the steps that you have listed here however my cayenne is 2005 v6 and it has one mass air flow sensor. I will grateful if you could give a guide as the plastic around it does not contracts like what you have show in the picture
December 28, 2015
  Followup from the Pelican Staff: The sensor has to be removed from the front duct, at the radiator support. Then unscrewed from the housing. We don't currently have that tech article. If we get a chance to perform the procedure, we will be sure to document it.

I would grab a repair manual. It will have the procedure, special tools and torque specs.

Give our parts specialists a call at 1-888-280-7799. - Nick at Pelican Parts
 
Kenny @ Mars Motoring Comments: Also, if the primary objective is to just replace the MAF itself, all one need is to perform steps mentioned in figure 4 and figure 8. There is no need to remove the housing as long as the removal is done with care without damaging the sensor itself.
November 29, 2014
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 
Kenny @ Mars Motoring Comments: That's a great write-up! Just a minor update on the last step figure 8: for some Cayenne, instead of T20, the MAF is secured by 2 screws that requires 5 point star tamper-proof 25IPR driver to remove.
November 29, 2014
  Followup from the Pelican Staff: Thanks for the additional info and feedback. We appreciate it.
- Nick at Pelican Parts
 

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