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Troubleshooting and Replacing the Mass Air Flow Sensor (MAF)
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Pelican Technical Article:

Troubleshooting and Replacing the Mass Air Flow Sensor (MAF)


1 hr






Tamper-proof T20 Torx driver

Applicable Models:

Porsche 986 Boxster (1997-04)
Porsche 986 Boxster S (2000-04)
Porsche 987 Boxster (2005-08)
Porsche 987 Boxster S (2005-08)

Parts Required:

Mass air flow sensor (MAF)

Hot Tip:

Try cleaning the unit first.

Performance Gain:

Smoother running engine

Complementary Modification:

Replace air filter.
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The mass air flow sensor (MAF) is located inside the engine compartment and is used to measure the amount and temperature of air that is entering the engine at any one time. Older style meters used on fuel injection systems in the 1980s measured air volumetric flow, which worked fine but then you also needed a separate sensor to figure out how cold or dense the air was. The mass air flow 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 MAF also incorporates an internal intake air temperature sensor which measures the temperature of the intake air.

The first indicator that you might have a problem with the MAF is the presence of a check engine light (CEL) on your dashboard. The check engine lamp can be caused by a wide variety of problems with the engine: you need to read the codes from the computer to get a starting clue as to what the problem is (see Project 20 for details on reading the codes). It's perfectly safe to continue to drive the car while the CEL light is on, as long as it is not flashing. However, the engine will not be operating at peak efficiency, and you will most likely experience a loss in power and a decrease in gas mileage as a result. It's best to get the problem taken care of relatively quickly, as running the engine in this condition can potentially cause damage to other components like the catalytic converters.

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 kick back an error code.

To gain more information about the problem, you can try disconnecting the sensor completely and taking the car for a drive. If you take short drives (30 minutes or less) with the sensor disconnected, it shouldn't cause any major damage to your car. The engine management system (DME) will enter into a type of "limp mode" that will compensate for the missing MAF. If engine performance improves dramatically when disconnecting the MAF, then the problem quite likely lies with the MAF.

Vacuum leaks and other air leaks in the system can 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. If the clamp on the throttle body happens to come loose and fall off, then the MAF will indicate almost no air being sucked through the intake, yet the engine will be sucking air directly from the engine compartment into the throttle body. The bottom line is that you should carefully inspect all of your hoses, clamps and intake tubes for air leaks prior to replacing the sensor (see Pelican Technical Article: Troubleshooting Vacuum Leaks).

The MAF is located on the left side of the engine compartment, just behind the air filter (see Project 3 for access to the engine compartment). For some reason, Porsche made it unusually difficult to remove the MAF, by securing it with a T20 tamper-proof Torx screw. You need the special tamper-proof Torx drivers which are not typically found in everyone's toolbox, but usually can be purchased at a good local auto parts store. Although the holes on the MAF look symmetrical, they are not and the unit can only be installed in one direction. See Photo 1 for a close-up of the MAF. Removal is easy, once you have the tool. Simply remove both screws holding it in place and pull it out. Boxsters from 2005 and later have a MAF with an integrated housing: simply unclamp the housing from the intake tube and remove it.

It's very important to keep the sensor clean. If the air cleaner isn't working too well, it could allow dust and debris to collect on the MAF. If you've had a problem with your air-oil separator, it could have contaminated the sensor as well. Oil sucked into the engine intake from a defective separator can easily find its way back to the intake tube. If you have had major engine problems (like our project car with the blown up engine), then you may find a ruined MAF. On our donor car, the MAF was soaked in oil and coolant residue that had found its way all over the engine. If you have an aftermarket reusable air filter, beware of how much cleaning and filtering oil you use on it. Excess oil may get sucked into the intake and find its way onto the MAF. To keep your MAF healthy, I recommend changing or cleaning your air filter often (see Pelican Technical Article: Air Filter / Pollen Filter Replacement).

If you are replacing your sensor, it is extremely important that you get the proper one for your car. There are two basic types, one for the cars that use a traditional throttle cable (up to 1999), and one for cars with an E-gas electronic throttle (2000 and later). In addition, the later-style E-gas sensor has been updated at least twice as of this moment. Porsche updated the sensors in the Boxster in mid-2000 and also released a new version of the DME software that is a required update if you are going to use this new and improved sensor (see Porsche Tech Bulletin Boxster 1a/00 2445). Here is a chart that shows the differences between all of the sensors:

Porsche Part #BOSCH Part #ApplicationNotes
996.606.123.000-280-217-0071997-99 All BoxstersSensor for use with cable throttle cars
996.606.124.000-280-218-009Early 2000 Boxster / Boxster SOriginal sensor for E-gas cars
(thru Boxster 2.7L Chassis #98 6YS 62 0414 and #98 0YU 62 5099)
(thru Boxster S 3.2L Chassis #98 0YS 66 0257 and #98 3YU 66 2413)
986.606.125.00Mid 2000-04 Boxster / Boxster SFirst updated sensor for E-gas cars
(discontinued and replaced with version 125.01 below)
986.606.125.010-280-218-055Mid 2000-04 Boxster / Boxster SLatest updated sensor
987.606.125.000-280-218-1452005- All Boxster / CaymanIntegrated housing design

If you own a 2000 Boxster or 2000 Boxster S, then you need to make sure that you have the proper sensor installed. Much confusion lies in the fact that most people don't know if their car has been updated by Porsche or not. If the old sensor that you removed is 996.606.124.00, then you need to replace it with the same part number (or have Porsche update your DME software to accommodate the newer style sensor: see Technical Service Bulletin 1/00 2445 Air Flow Sensor -- dated 4-18-00). If the old sensor you're removing ends in 125.00 or 125.01, then replace it with 986.606.125.01 (the latest version available).

After reinstallation, reset your check engine light (CEL), using your code reader (see Pelican Technical Article: Reading Fuel Injection Fault Codes / Diagnosing Problems). You can also disconnect the battery for a short while to reset the lamp, but I don't really recommend this approach (see Pelican Technical Article: Reading Fuel Injection Fault Codes / Diagnosing Problems). On 1997-02 Boxster, you can disconnect the battery for more than 20 seconds, but less than 50 seconds to clear the trouble codes without having to enter your code back into your radio. On pre-2003 cars, the computer's CEL memory is cleared after being disconnected for 20 seconds, but the radio code is needed after 50 seconds disconnected.

After you have replaced or cleaned the sensor and cleared the code, you need to go drive the car and see if the code returns. 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 secondary air injection equipment problems 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 the mass air flow sensor (MAF).
Figure 1

Shown here is the mass air flow sensor (MAF). The main sensor fits in a hole in the air intake right downstream of the air filter. The green o-ring seals the sensor to the intake tube (yellow arrow). If you're having trouble with your MAF, you can try to resurrect it by cleaning it. Lightly spray the areas shown with the blue arrow with electrical contact cleaner: the one that I recommend is CRC Mass Air Flow Sensor Cleaner. Spray it and then shake the sensor so that any dirt or debris is washed away. Don't touch any of the sensor elements with anything (like your finger or a brush), as this will damage them almost immediately. Let it dry completely prior to reinstallation.

You need a T20 tamper proof Torx bit (inset upper left and lower left) to remove the mass air flow sensor from its home in the intake pipe (yellow arrow).
Figure 2

You need a T20 tamper proof Torx bit (inset upper left and lower left) to remove the mass air flow sensor from its home in the intake pipe (yellow arrow). It's typically easier to pull the sensor out of the intake tube first, and then disconnect the electrical harness. Be sure not to touch any of the sensor elements that are exposed (red arrow). Clean the entire housing area prior to installing your new sensor.

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Comments and Suggestions:
Ricky Comments: Hi, so i have a 2000 nissan altkma GXE, and i'm having problems with themass air flow system. I recently bought a manufactured mafs because my car would stall out. It worked fine but then i had to change the socket because it would accelerate hesitantly. So i bought a brand new mafs and bought 7 sockets from a junkyard. I spliced the wires and changed the socket. It was fine for a few days, but started acting up again so before i changed it i pushed it in deeper or moved the socket. It acted up after a while of running fine again. So i changed the socket to another one, it was fine, and then it acted up again, i moved the socket and it was okay for a while and then after bumps or high speeds it would immediately act up again. I've changed most parts, except IAC and throttle position sensor, distributor, catalytic converter, you name it i'll answer. I just wanna know what other steps can i try in order to keep my car idling fine and running fine, i'm spending 10 dollars on gas every day or two trying to figure it out.
November 20, 2015
  Followup from the Pelican Staff: I don;t know much about your model. However, you can;t splice in a different maf sensor. You have to use the correct one with the right part number and connector. I would start there. - Nick at Pelican Parts  
NewPorscheGuy Comments: I have a 1999 986. It will start and idle fine, but when yopu push the throttle it just bogs. I have replaced the fuwel filter with no change. What am I missing? Is there a senser I need to replace? There are no Porsche mechanics in my area to ask.
September 29, 2015
  Followup from the Pelican Staff: Could be an issue with the fuel pump. I would perform a fuel delivery system test. Check fuel pressure, volume and quality.
- Nick at Pelican Parts
Paul in KY Comments: Ok got my MAf today in the mail FINALLY. I got out, take apart all the covers, take out the old one, install the new one and BAM! revving bad like it is starving for fuel. Like how a bad MAF actually sounds. Did not figure out the arrow until I was done stupid me. So I put it in the other way thinking it was in wrong. Again really bad running. SO I put in the old one and we are running fine again. Normal revs, normal acceleration, just like before. Questions:
1. IF the MAF is bad, I would assume that the revs would in fact be terrible correct?
2. IF the MAF had a bad plug would I be safe in assuming that the revs would, again be bad.
3. Can the O-ring affect how it "revs"? In other words the O-ring on the new one looks to be really flimsy and not quite the same size. Would I get a bad seal, thus producing the bad running bad revving?
4. IF the O-ring is in fact part of the problem, should I just switch them out and see what happens? OR
5. Should I just clean the old MAF and see if I get a CEL again? Thoughts?
July 18, 2015
  Followup from the Pelican Staff: 1. Could be.

2. Sure. has to work electrically.

3. Yes, if it doesn't seal well, you will have unmetered air.

4. Worth a try.

5. Cleaning a hot film mass air flow sensor can ruin it.- Nick at Pelican Parts
dru Comments: Please help!! i have audi a3 2000 model i just bought a new maf sensor but the car does the same thing idles and cuts off can't even drive for 500 meters! but funny thing is when i disconnect the pipe from intake and leave maf sensor connected it idle very good, whn i put back the pipe it cuts off , it does not want the air from the sensor, what might be the problem
June 28, 2015
  Followup from the Pelican Staff: What is missing when it stalls? Check spark, fuel injector pulse and fuel pressure, volume, quality and engine compression. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose. - Nick at Pelican Parts  
mus adem Comments: vw 2004 touran the engine is one minute is dying and then picks up again the rev counter is up and down is it anything to do with iar intake
May 25, 2015
  Followup from the Pelican Staff: Could be a vacuum leak or a misfire. - Nick at Pelican Parts  
Radu Comments: I took out my sonsor, cleaned it and saw thet it was missing the wire, i bought a new one and that one had a missing wire too, now is it normal to not have the wire on some models or did i get ripped off by Bosche? The sensor is bosch f00c2g2055
May 20, 2015
  Followup from the Pelican Staff: What vehicle? Yours may be a hot film sensor. - Nick at Pelican Parts  
Lisa Comments: It started out we replaced the A/C compressor because it was bad. The mechanic had it running fine and idleing fine with no issues. I had replaced the air filter about a week before but I didn't get the case shut all the way so while I was there he showed me how to take off the hose and shut the case all the way down. While he was doing that, he was explaining about the MAF. When he was done, I left and when I left everything was running fine. I got 2 blocks up the road and all of a sudden the car started cutting out, no throttle, and it was idling crazy, up to 2 down to .5. I barely made it back for him to see what was happening. No real codes but when he tapped on that part, it started acting totally crazy so we replaced that MAF. At this point, I have tried to get it to "learn" the senses that it needs to work correctly but just sitting in park, the engine will rev up to 2 then down to 1 then back up and back down, it does not do this when it is in gear. I'm at a loss. :
May 6, 2015
  Followup from the Pelican Staff: It sounds to me like the car needs to have the fault codes scanned from the ECU. One thing you could try is to perform a throttle body cleaning. Carefully clean the throttle body and then perform a throttle adaptation. The throttle adaptation is usually performed by turning the key to the "on" position without starting the car. Leave the key in the "on" position for 60 seconds. Then turn the key back off and try to start the car. My guess is that some dirt or gunk got up in the throttle and is making it hard for the car to control the idle speed. Let us know how it goes! - Casey at Pelican Parts  
Lisa Comments: I just had the MAF replaced on my 2005 Nissan Altima. It idles great when it's in gear, but now when it's in park it idles at about 1.5 RPM. This doesn't seem to be normal but could it be from the MAF having to reprogram itself?
May 5, 2015
  Followup from the Pelican Staff: Why was the MAF replaced? For a fault code? You probably have a vacuum leak. - Nick at Pelican Parts  
BluSmokers Comments: I have a Buick Roadmaster limited edition 1994 in year. My problem with my vehicle is that while I'm driving the car will go dead or shuts off and then it takes 15 or 20 minutes to start-up. I have replaced the fuel pump, fuel filter, plugs & wires. I don't know if it's a sensor bad or what. It goes dead or shuts off more when it's hot outside than its colder. Could you give a diagnosis to my problems please.....
April 4, 2015
  Followup from the Pelican Staff: I can't help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and fuel pressure, volume, quality and engine compression. Are there any fault codes? Once you figure out what is missing, it will be easier to diagnose.
- Nick at Pelican Parts
Sam Comments: Hi guys, I've got a 1997 2.5 Boxster with an issue I'm struggling to diagnose.

Initially the car started and would respond to the throttle for the first 5 seconds or so, but after a few seconds it would start to misfire and wouldn't rev past 2000 rpm due to the misfires, the idle then gradually slows until it stalls after about 30 seconds.

I thought it might be a fuel issue, sprayed some starer gas into the intake and the engine would run and rev on the gas for as long as I sprayed the gas.

However if I disconnect the MAF the engines runs ok not great, but it’s driveable it’s a bit rough if I open the throttle too quickly, but it runs perfectly past about 3000 rpm and feels like full power is there.

So it looks like fuel and ignition is ok and the MAF is playing up. I bought a secondhand MAF from a breaker same part number but now the car doesn’t start. The engine catches, but dies a split second after releasing the key, even if I give it a load of throttle.

There are no fault codes using a generic ODB2 cable, and the check engine light isn’t on. I disconnected the battery for a minute to reset the ECU after installing the second MAF.

I’m planning to order another MAF in case both are faulty. I’m just wondering what else it could be. If the crank position sensor is playing up, would the car run ok without the MAF connected?

I’ve inspected for intake vacuum leaks, but it visually all looks ok, and I can’t believe there is that big a vacuum leak that the car doesn’t even start with the second MAF. However with the MAF disconnected and the engine at idle I removed the oil filler cap, and there is no vacuum under the cap? could a crankcase leak cause the engine to not start, or die after 30 seconds as with the first MAF?

Would faulty O2 sensors stop the car from starting while the system is still cold and in in open loop? I can see from my ODB2 cable that both sensors are returning plausible voltages with the MAF disconnected it’s an EU car so just 2 sensors

The car doesn’t smoke excessively so I don’t think it’s a failing AOS.

Your site has been a great resource so far. Thanks for any help.

November 23, 2014
  Followup from the Pelican Staff: Disconnecting the MAF is not a good test.

You need to check spark, fuel delivery and compression when the problem is present. One of those will be faulty. - Nick at Pelican Parts
Chris Comments: CEL has just come on my 986 Boxster 2.7 2003 after it has been stood in the garage for the last two weeks. Took it for a run and it drove well considering it hadn't been used for a while. Disconnecting battery hasn't removed light. Only covered 6,000 miles in last couple of years so putting it in for a minor service next week. Could it be a faulty the MAF?
November 21, 2014
  Followup from the Pelican Staff: Impossible to guess without knowing what code is stored.
I would start by checking the DME for fault codes. If the system is not working properly, a fault code will be set. This will be your best bet when diagnosing.
- Nick at Pelican Parts
jd23 Comments: I just recently changed my MAF sensor. My car runs better, but sometimes it struggles to start. Before I changed it to the new one it would ride bad, but it would still always start easily. Is the problem that I didn't reset the check engine light after replacing it? Please reply
October 24, 2014
  Followup from the Pelican Staff: It could be. Clear the check engine light, if the problem remains, your new part may require a software update. - Nick at Pelican Parts  
Vito Comments: Ok, I get a p0507 code in my 2001 boxster. Ive cleared it and when I do, the idle goes to where it is supposed to be. If I drive within city on small spurts, the code comes back after 20miles or o, but if Drive on long runs highway, or where I can wind out a bit, the code does not come back. I also got a p0128 and p0130 code once as well... I am leaning towards MAF issues, after reading these notes...Any feedback???
October 21, 2014
  Followup from the Pelican Staff: Check for air leaks on the intake air ducts. If there are none you could have a faulty maf or throttle housing. - Nick at Pelican Parts  
erick Comments: OK, so I'm one of those sorts of idiots that lost one of the MAF mounting screws while reassembling after a test/clean. Where can I find a replacement screw?
September 21, 2014
  Followup from the Pelican Staff: A hardware store is your best bet. - Nick at Pelican Parts  
claw Comments: I have a 2011 Altima with 2.5! Trouble code said maf malfunction. I replaced it and all was fine for 4 days and light reappeared with same code! Any idea what might cause this?
September 15, 2014
  Followup from the Pelican Staff: I can't be too specific without knowing the fault code. COuld be a defective sensor, air leak or wiring issue. - Nick at Pelican Parts  
fire1932 Comments: 1999 pont grand am v6. idles fine until i start to drive then it dosen't idle down for several seconds. idle stay high until i slow down
June 10, 2014
  Followup from the Pelican Staff: Could be a vacuum leak or a bad idle control motor. - Nick at Pelican Parts  
jeffw Comments: I have a 2000 Boxster S. It appears I have a problem with my MAF since it runs fine when disconnected. I cleaned it with no change. The one that is in there is the Bosch replacement for 124.00. The dealer told me they replaced it just over a year ago 2500 miles. The VIN shows #98 4YU 66 4608. Could they have put in the wrong one? Which one should I order? thanks
June 7, 2014
  Followup from the Pelican Staff: I can't imagine a dealer would put the wrong part in. Give our parts specialists a call at 1-888-280-7799. They can help check the part numbers. - Nick at Pelican Parts  
andrew c Comments: Hi there.
So I cleaned the mass sensor in my 97 Tacoma did this very carefully aslo did a bit cleaning on the throttle body. Everything seemed to be fine for the first 45 min of driving. When I stopped at a driveway a bit up hill I realized that my temp gauge was rising I quickly turned it off waited abt 5 minutes went for another 15 minute drive no sign. Of temperature
rising. Is this something that can possibly happen after cleaning any help would be greatly appreciated . Thanks
May 20, 2014
  Followup from the Pelican Staff: The problem does not sound related to cleaning your MAF sensor. - Nick at Pelican Parts  
robtheboxsterguy Comments: I have a 2001 boxster throwing the codes of P1128 and P1130. My local european shop claims that the MAF needs to be replaced. I am skeptical of this analysis and will try and clean the MAF and change out the air filter. If this doesn't work any idea of where to check next? I think my air oil seperator is fine. As tested after removing the oil cap doesn't make any change in RPM's and also it is not pulling air through in a big way. Thanks in advance
May 14, 2014
  Followup from the Pelican Staff: Cleaning a hot film MAF is not effective. I would check fuel trim, max kg/h and calculated load. - Nick at Pelican Parts  
CEDARMIKE Comments: 03 Mercedes 240 replaced MAF after 60K...went out after 2 on 3rd MAF..Electrical system checked by foreign auto shop during a 4 day stay @shop. All other components maintained by foreign shop. MAF wire seems to look BURNT.
May 14, 2014
  Followup from the Pelican Staff: Is there water entering the intake air box? I would start there. - Nick at Pelican Parts  
Ayan Comments: Hi, I have a 2005 chevy cobalt. No engine light shows up on my dash but at random times my car loses power. Everything is working in terms of lights but when i push the acceleration, it doesn't go and the only way to temporarily fix the issue is to stop the car, put it in park, and then turn the car off and then back on. Everything works fine after that. What could the issue be?
April 10, 2014
  Followup from the Pelican Staff: You could have a fuel delivery problem or restricted exhaust. - Nick at Pelican Parts  
jimbot Comments: Hi. I've had two new MAFs in the last few years. But same issue - during long journeys or after traffic jams 2001 automatic Boxster S fails to accelerate from a standstill. Accelerator does not respond for 2-3 seconds and then jumps into life. Will be ok for a few minutes, then does the same again at the next junction. Sometimes the engine will cut out if I don't ease off the gas when it happens. Occasionally it will hesitate when travelling along in 3 or 4th gear but mainly at junctions from a standstill. No errors on the computer say garage. Engine temp is normal at around 80. I've also had a gearbox oil change and a new throttle body as attempts to fix this issue. After gearbox oil change car was fine all Winter, but now Spring temperatures are here the problem has returned. Thanks in advance.
April 6, 2014
  Followup from the Pelican Staff: Could be a fuel delivery issue. I would perform a fuel delivery system test. Check fuel pressure, volume and quality.
- Nick at Pelican Parts
Jamez Comments: Thanks. Fuel pressure is fine. Flat spot occurs between 3000 - 4000 rpm in all gears. Can this be caused by a faulty Knock Sensor, Throttle Position Sensor or O2 sensor? Thanks.
February 7, 2014
  Followup from the Pelican Staff: Knock sensor, unlikely. Could be fuel volume or exhaust backpressure issue. - Nick at Pelican Parts  
John Comments: I've met several technicians. the vehicle moves and stalls, makes a lot of sounds and jerks when it wants to accelerate. the fuel filter was changed

and after then, the vehicle moves and stops. Later the airflow was changed.presently it doesn't start until I remove the airflow. the vehicle

doesn't accelerate and still jerks
January 27, 2014
  Followup from the Pelican Staff: I would perform a fuel delivery system test. Check fuel pressure, volume and quality.
- Nick at Pelican Parts
Jamez Comments: Hi, I have a 2000 Boxster S MY 01. Noticed intermittent acceleration flat spots with no codes. Replaced Bosch MAF 986.606.125.00 with Bosch 986.606.125.01 still the same flat spots. What might it be? Does the DME need updating for the revised MAF? Thanks, James.
January 21, 2014
  Followup from the Pelican Staff: The DME update is usually done when the MAF is upgraded However, I know many people that have NOT done it and been fine. Have you check fuel pressure, etc? - Nick at Pelican Parts  
vreel Comments: Oh, the car is a 1999 Porsche Boxster.
December 13, 2013
  Followup from the Pelican Staff: Thanks, got it. - Nick at Pelican Parts  
vreel Comments: Still having issues. My vehicle idles great. When I press the accelerator slowly there are no problems. When I gas it semi quick the motor cuts out. If I gas it very quick it almost dies and then one second later the engine revs strong. I unplugged my mass air flow sensor and there is no change at all. I purchased and replaced the old one and zero change to the motor. I have also replaced the fuel filter. I also hear a loud whine and air noise coming from the motor. Possible vacuum leak?
December 13, 2013
  Followup from the Pelican Staff: Sounds like a fuel delivery issue. I would perform a fuel delivery system test. Check fuel pressure, volume and quality.
- Nick at Pelican Parts
Larry Comments: Your articles are very well written and easy to follow. However, I am having a problem with my 98 Boxster MAF. The code I am getting is P0102, MAF or VAF A circuit low input. I bought THREE new MAF's with TWO being Bosch. With the old MAF, car runs great. Once a new one is plugged in it hardly idles and dies often. Unplug the new sensor, car runs smooth. Again, with the original one, car runs fine except after clearing the code, the light comes on after the second time I start it. Still runs good, but the CEL is on.. Any ideas? Attached is one of the replacement MAF's I received. Thanks.
November 22, 2013
  Followup from the Pelican Staff: If I remember correctly, there may be a software update to go along with an updated mass air flow sensor. At the minimum, you should clear the adaptations. - Nick at Pelican Parts  
albert Comments: The car has a bad fly wheel but still runs u think maybe that can make the crank sensor not wk that good.
November 20, 2013
  Followup from the Pelican Staff: You didn't mention what vehicle you have.

If the crank sensor reads a toothed wheel on the flywheel, and the flywheel ha s mechanical issue, it could cause a fault with the crank sensor. - Nick at Pelican Parts
albert Comments: on my 1999 Chrysler sebring my car starts like normal and runs good but when i drive for like 30 40 min it shuts off when i start to slow down and dosnt start back up for like 3 to 4 hours it starts up normal could the maf cause the problem.
November 18, 2013
  Followup from the Pelican Staff: No. that sounds like a crank sensor or fuel pump. I can't offer specific help without knowing what is missing from the system when you are trying to start it. When your engine doesn’t start you’ll want to check the basics. Check spark, fuel injector pulse and pressure fuel, volume and quality. Once you figure out what is missing, it will be easier to diagnose. - Nick at Pelican Parts  
Charlie Comments: CEL: OBD2 Codes: 1023 1025. Boxster 99. 55K. nOV 2 2003

1023 in 20 miles followed by 1025 in another 10. Researched says possible MAF gone south. Other symptoms, LTFT running in the 20% range, and definite hesitation when hard accelerate from 3500-4500 RPM range. New MAF in and nO CEL codes. 220 miles and counting:-
November 4, 2013
  Followup from the Pelican Staff: Thanks for the additional info and specs. This will certainly be helpful to someone in the future. We appreciate it.
- Nick at Pelican Parts
White63 Comments: Hi guys. I read with big interest your great guide and I thank you in advance! My problem: I own an early 2001 2,7 lt Boxster whose VIN is WPOZZZ98Z1S600740 and I'm not sure if it was one of the updated ones by Porsche or not. Since my Box is over 150K Km I think it would be time to change it instead of trying to simply clean it or am I wrong?. NB: my MAF was never changed before. Could you tell me by the VIN without having to access the engine compartment if I should buy the 124.00 or the 125.01? Thanks a lot.
October 13, 2013
  Followup from the Pelican Staff: I think you want the 125.01. To be sure, give our parts specialists a call at 1-888-280-7799. They can help you find the right sensor.
- Nick at Pelican Parts
cococal Comments: my 1998 boxster will not start
October 12, 2013
  Followup from the Pelican Staff: If your engine doesn’t start you’ll want to check the basics. FIrst check the battery. If the engine cranks but doesn't start, check spark, fuel injector pulse and pressure fuel, volume and quality. Once you figure out what is missing, it will be easier to diagnose. - Nick at Pelican Parts  
Dunny Comments: Have an 02 996 and have recently experienced a throttle hesitation issue after driving for an hour or more or driving the care a little hard.Have informed 2 mechanics that I believe it is the maf sensor but they disagree as there are no codes being thrown. It can be a little dangerous for example engine will stall at take of from lights once the issue begins. Neither mechanic can replicate the problem after driving for about 20-30 mins. Am interested in your thoughts
September 29, 2013
  Followup from the Pelican Staff: An intermittent hesitation is tough to diagnose. This could be the MAF as you suspect or a fuel system issue. If you suspect the MAF and feel strongly about it. have them replace it. If it doesn't fix it, you have one item out of the way that could cause the issue. - Nick at Pelican Parts  
ggmom Comments: jt had maf sensor rePLaced on 2010 ford f150. no warning lght, did not show up on fault code as anyuthing wrong, but when dealer removed it andd replaced it truck ran. it hAd a sudden, complete loss of power while driving doWn highway WOULD NO LONGER RUN, TOWED TO DEALERno matter what test they ran everythin showed normal. only removing and replacing sensor seemed to corret problem. sure hope so. l7,000 miles on truck
September 13, 2013
  Followup from the Pelican Staff: Hope it works out. That is low mileage for the sensor to fail. - Nick at Pelican Parts  
Mike Comments: I have a 2000 Boxster S and I had a fault code indicating I had a faulty Mas Air Flow Meter. I had a local mechanic read the faults. I had never worked on a car before, but decided to replace the part myself after getting a quote of $850. Getting the top released and engine exposed was a little bit of a learning process but the directions on Pelican were great and Porsche builds one incredibly put together car! I was able to replace the part, reset the check engine light and put it all back together in 3 hours. Thanks Pelican for great directions and I am happy to report the car is running like brand new again!
September 12, 2013
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help. - Nick at Pelican Parts  
DeeDee Comments: The insurance purchased a used engine replaced for my 2000 bruick lasabre custom,afterwards it would not insurance company paid for the replacement engine.I took it back to the garage that replaced the engine. Would the MAF be a part of the engine cost. It would not run after I had the engine replaced. The question is whether the MAF was possibly bad on the used engine replacement?
September 11, 2013
  Followup from the Pelican Staff: I wouldn't be able to tell you if the MAF is covered as par tof the engine. Check your insurance policy. It should list what is covered when an engine is replaced. The MAF could have been bad if it was from the used engine, you should ask the shop to put your old MAF on.- Nick at Pelican Parts  
Patty Comments: I just changed my MAF sensor last night in 02 Boxster. Car runs like new! Followed this tech article and it made the job simple. Thank you!
September 6, 2013
  Followup from the Pelican Staff: Thanks for the feedback. Glad we could help. - Nick at Pelican Parts  
tecrep Comments: No I don't see a difference when I unplug maf sensor but since the weather cooled off its been running better at normal operation but if u stomp on it it will cut out and die
September 5, 2013
  Followup from the Pelican Staff: It could be the MAF or a fuel delivery problem. I would check the output voltage of the sensor and test the fuel delivery system. - Nick at Pelican Parts  
GregM Comments: Hi,
I bought a new MAF sensor for my 1998 986. After replacing it I got some electronic engine troubles engine rattle, stopped, didn't restart, finally restarted, but generate missfires.
I was wondering if the ECU need to be reprogrammed after the sensor replacement. I also noticed that my old sensor has the ref.996.606.123.00, while the one I bought is 996.606.123.00-M14. Is this M14 a revision number so something similar indicating any ECU reprogramming requirement?
September 4, 2013
  Followup from the Pelican Staff: M14 refers to the amount of times this part has been modified or revised. The DME may need to be updated, the only way to tell would be to check the software number against the latest. - Nick at Pelican Parts  
tecrep Comments: Have a 89 Pontiac 2.8 flags code 33 witch is the maf sensor it cuts out sometimes dies and sometimes hard to get started again when its cutting out I smell fuel can this still be the maf sensor
September 2, 2013
  Followup from the Pelican Staff: Could be. I would test the MAF sensor. if you unplug the MAF, does it run better?- Nick at Pelican Parts  
vreel Comments: Hi, I'm not sure what is wrong with my vehicle. 1999 Porsche Boxster Auto. Car idles good, but when I accelerate, the vehicle cuts out and losses power then regains the power a couple seconds later. If I accelerate very slowly there are no problems. I changed the fuel filter.
August 29, 2013
  Followup from the Pelican Staff: Sounds like you have a bad mass air flow sensor. Before replacing it, check the DME for fault codes. If the system is not working properly, a fault code will be set. This will be your best bet when diagnosing. - Nick at Pelican Parts  
mpd98 Comments: Hi, I have exactly the same problem as Jim; a new MAF was fitted, battery was disconnected to reset ECU, and although it runs fine, it's not quick like before and at certain points of the rev range it's just so quiet! Pumping the gas pedal a little brings back the noise and fury. No codes are being thrown up. Any ideas?
July 5, 2013
  Followup from the Pelican Staff: It could be a weak fuel pump also. Have some step on the gas while you add carb spray down the air cleaner duct - Nick at Pelican Parts  
Blake Comments: Hey I just purchased a 2000 Boxster S with 62,XXX miles on the clock and on the PPI they said it needed the 60k service and a oil air separator. I decided to perform all the work myself Plugs, belt, air filters, fuel filter, Oil air separator, Oil change and filter, I also took the throttle body off and cleaned it with carb cleaner. My buddy came over as I was getting done with the car and taking it off the stands and had a OBII code reader that we plugged into the car after the initial startup and cleared the codes since I replaced the oil air separator which had a bad hose causing a vacuum leak and I wanted to see if the CEL would return for any other reasons. The car seem to idle fine before we cleared the codes but didn't try to rev or give it any gas but after we cleared the code he said turn the car off and turn it back on but when I restarted it the car it idled really ruff and won't take gas. It seems to idle up and down from 700ish-1200ish. I can barely press the gas and get a smooth idle at 1000-1200ish but won't take any more gas then that. Note that we took the battery negative off for 20 mins hoping that would reset the computer or whatever is causing the erratic idle and throttle not being responsive. Thanks in advance
June 4, 2013
  Followup from the Pelican Staff: I would start by checking the DME for fault codes. If the system is not working properly, a fault code will be set. This will be your best bet when diagnosing.

The adaptations may have been cleared during your service work. Try turning the key ON (without starting the engine) for about about a minute. Then turn it OFF for a minute, then back ON for a minute. Once done with this cycle, try starting the vehicle again. - Nick at Pelican Parts
Jim Comments: I got the CEL light and a local Porsche specialty shop diagnosed and replaced the MAF sensor. The car now runs smoother but has much less jump and power than it previously had. Further, it has a much quieter sound. My fast fun car has become a slugish cruiser. The shop suggests this is normal. In your opinion is this typical of a MAF change and if not what do you suggest has happenned and what should I do?
May 14, 2013
  Followup from the Pelican Staff: Replacing the MAF sensor should restore lost performance, not necessarily degrade it. Have them check the vehicle and see if everything is installed correctly and no fault codes are stored. - Nick at Pelican Parts  
Upnorth Comments: Guys, no need to go and buy a T20 tamper proof torx bit ... Just take a 1/16 drill and "create" your own. Piece of cake
April 20, 2013
  Followup from the Pelican Staff: Great tip. Thank You!  
Craigieboy1 Comments: Help! Just had new stage 1 exhaust, ipd plenum and 74mm tb installed along with cold air intake. As part of work, aos was replaced and water pump. She's now idling badly and running worse. Improves when I remove maf or if I take off oil cap. You can hear hissing and feel vacuum when removing the oil cap or dipstick, but it wasn't hard to remove so I'm guessing that points to a crankcase leak somewhere?
March 15, 2013
  Followup from the Pelican Staff: You'll want to double check AOS connections. Keep in ind, removing the oil cap will create a vacuum leak and change the way the engine runs. Are there any fault codes stored? - Nick at Pelican Parts  
Paige Comments: I'm trying to figure out the type of MAF I need for my 2000 Porsche Boxster it has the smaller engine.. My vin is 2987YU624042 and it doesn't match up with any MAFs here. Which one would be right for my car?
November 26, 2012
  Followup from the Pelican Staff: Give our parts specialists a call: 1-888-280-7799 They will help you find the right MAF sensor. - Nick at Pelican Parts  
Kaan Celebi Comments: Good morning, I am about to purchase a MAF for my 2001 Boxster, I believe the part number is 986.606.125.01. The VIN is WP0CA29801U623269. Could you confirm before I order it online? Thank you, Kaan.
November 6, 2012
  Followup from the Pelican Staff: Give our parts specialists a call: 1-888-280-7799 They will help you find the right MAF sensor. - Nick at Pelican Parts  
Osio Comments: After detailing my 2000 Porsche boxster started it and for a moment it ran ruf no CEL light on but it would not rev over 1800 RPM The shop changed the throttle body.After clearing the code 1502 it went in to limp mode again.After that they said it needs a new ECU.After that I payed the bill of $1095 and took the car home Still trying to learn something about this problem.I would greatly appreciate if someone could possibly help me with this headache.Regards Osio
September 6, 2012
  Followup from the Pelican Staff: That's odd considering the new control unit lists for 2348.02. Maybe they got a rebuilt one. The ECU looks for the MAF signal to match and expected reading compared to the throttle opening. MAF vs. TPS. Any air leak in between the intake and the MAF could also cause the problem but maybe your computer stopped working properly. Did you accidentally get water in the ECU? - Nick at Pelican Parts  
designprof Comments: I have a 1999 Boxster that was giving me P1124 and P1126 codes. I replaced my MAF, and reset the cel by disconnecting the battery for about 1 minute. All was great and the car ran well. Next day rough start - coughing and not able to idle. Reset cel again and all is great. Next day, same thing! Why is the ecu not adapting to the new maf? What am I doing wrong?
September 5, 2012
  Followup from the Pelican Staff: You may have a vacuum leak. Anything that throws off the mixture can make the car run rough. When you disconnect the battery the ECU forgets all the adjustments it learned to correct the mixture problem. Check for possible vacuum leaks - Nick at Pelican Parts  
rodgers Comments: i changed mafs on nissan altima runs fine but it jerks some when i go 45 does it reboost itself in time cuz no codes on or engine light not on
August 28, 2012
  Followup from the Pelican Staff: You may have an engine misfire. I would look into that possibility. - Nick at Pelican Parts  
Brian Comments: I have all the signs of MAF issue. check engine light with applicable codes. But just yesterday, it started roughly and then would only idle. Nothing would happen when I pressed the gas pedal. No acceleration or engine rev at all. I turned off and on the car a bunch of times before it finally worked. Could this be part of the same issue. If not. Any other ideas!? It's a 2000 boxster s.

Thanks. Brian
June 4, 2012
  Followup from the Pelican Staff: The ECU compares the Throttle position and the mass-air flow. Any thing that throws off that relationship can cause the problem, dirty MAF, vacuum leak, dirty throttle plates, etc. - Nick at Pelican Parts  
JDUB Comments: I have a 2011 Cayman S.
Do you offer a replacement MAF sensor for this version of the car?
May 11, 2012
  Followup from the Pelican Staff: We sure do - you can check our catalog, or give our sales guys a call at 1-888-280-7799. Thanks! - Wayne at Pelican Parts  
JJ Comments: The maf sensor installed currently on my car that needs to be replaced has this part number- 996.606.125.00. Which maf should I order? Should I go with the 986.606.125.01 as advised by this article? The vin on my 2001 Boxster S is WPOZZZ98Z1U640725. My engine number is M96/2167102466. I'm just making sure because I was told that most electronic parts, such as MAF are not returnable.
March 17, 2012
  Followup from the Pelican Staff: Yes, the correct (and only available version for your car) is the latest version of the updated one - 986.606.125.01- Wayne at Pelican Parts  
Stan Comments: I have a 99 boxster. Last week driving home from church my lil b started idling all funny. idle would just fly up and down between 1400 and around 2000 rpm.
Reading up on forums i was pretty sure it was the maf as when i unplug car runs fine and dont miss a beat. Pluging it back it in it goes back to the same problem.
I replaced the maf sensor with one from buy-auto and when i plug it up same problem. Buy auto parts offers 1 year of warranty and is an authorized bosch seller.
What did i do wrong?
I do have techart intakes with k and n if that helps. As well as tpc supercharger kit with other bolt ons.
February 13, 2012
  Followup from the Pelican Staff: Try disconnecting the battery to clear the ECU adaptations. Also check for a vacuum leak as this can also throw off the mixture. - Nick at Pelican Parts  
roanokebarry Comments: I wish I had read this blog before having my maf replaced cost me over 700 bucks....
January 8, 2012
  Followup from the Pelican Staff: Thanks for the feedback on the article. - Nick at Pelican Parts  
Jwplumber Comments: I replaced the stock air filter on my 2001 boxster with a k&n two days later the engine light came on. I am told that this is commen due to the amount of oil the company puts on the filter interacting with the mass airflow sensor. I used the suggested cleaner and so far it is off. Thanks this site is great it has always helped me with repairs on my Porsche .
September 24, 2011
  Followup from the Pelican Staff: Yup, I'm not a huge fan of "reusable" filters, as I don't believe that they filter as well as the stock units. I have one of these on my own Boxster, but that's because we have a special cold-air intake system that we had to install when we put in the 3.4 engine. - Wayne at Pelican Parts  
Croman Comments: I purchased a 2000 boxster last year and soon after the cel light came on. I took it to the local Porsche dealer and they said the mass air flow sensor needed replacement. They did so as well as checking out the car in general. Before the light came on the car ran rough at times. This year I am having the same problem - running rough when accelerating. I removed the MAF and it appears to be very clean. The number on it is 996.606.124.00 I never saw the one they took out. My boxster was dated 07/99 and the vin is
WPOCA2983YU620148 - looking at my gas pedal it looks like a cable comes from the unit. My question is do I replace the MAF and if so which one?
PS...Just took a 20 minute drive w/o MAF connected and it ran great and didn't miss a beat.
June 15, 2011
  Followup from the Pelican Staff: Yes, it would appear to be a fault with the MAF, particularly if you unplug it and it works fine after that. I'm not sure what the dealer did - I would buy one from Pelican and replace it yourself. Also, if you have a K&N style air filter that uses oil and doesn't filter as well as the OEM unit, then you might experience this as well. - Wayne at Pelican Parts  
keith sp1 Comments: recently changed the maf on my boxster s by following your superb instructions,saved some money by doing so to.great job guys many thanks.
April 24, 2011
  Followup from the Pelican Staff: No sweat! - Wayne at Pelican Parts  
Joe D Comments: I recently Installed a softronic Flash and racing plenum in my 2006 boxter non-S version. The car have been running great. But since the installation my check engine light has come on 3 Seperate Times. The flash and plenum were installed by my Porsche Dealer. So far they have not been able to figure out whats causing the issue. Installation has been checked and a re-installation was done, problem still exists. we are now trying a replacement of the sensor. Has this scenario happened with other similiar installations and are we going in the right direction
March 16, 2011
  Followup from the Pelican Staff: Yes, these types of issues are common with flash upgrades and non-stock modifications (unfortunately). I would contact Scott Slauson at SoftTronic and perhaps he can assist you with debugging the problem. - Wayne at Pelican Parts  
boxsterg Comments: I recently purchased a 2000 boxster with cel light on. I've cleaned the maf, replaced the air filter, checked for any leaks etc. Code reader says maf. My chassis is 4yu623351 my current I'm assuming not stock maf only says PBT-GF-30 which sensor do I need.
March 3, 2011
  Followup from the Pelican Staff: There should be a BOSCH part number on the sensor itself, you should be able to see it there on the side. Your chassis number is not familiar to me, can you post the full VIN on the forums and I will check the PN with the Porsche parts diagrams. - Wayne at Pelican Parts  
Will Comments: I did exactly as this article said and cleaned my MAF and everything worked perfect! Thanks for everything!
November 9, 2010
  Followup from the Pelican Staff: Cool deal, glad it worked out for you! - Wayne at Pelican Parts  

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