Mass Air Flow Sensor

[my996]

Thanks - I got it.

[Loren]

If it is not too tight then you might get it off with one hand (as in photo 1). If it is on tight then grab the other way (photo 2) and then pull with the other hand while squeezing.

[wazoo]

If it is not too tight then you might get it off with one hand (as in photo 1). If it is on tight then grab the other way (photo 2) and then pull with the other hand while squeezing.

Loren, I tried this...I have no idea how this is supposed to come out...the only thing I was able to accomplish was to unscrew it and pull it out...I have a 2000 MY C4...and the MAF looks different than in the photo. There's a rubber boot and plastic but without the screws, nothing pulls out.

My neck is sore, btw. I have no idea who designs this stuff, but it wasn't designed for "serviceability"...that's for sure! :beer:

[Loren]

Do you have a photo of it?

[wazoo]

Do you have a photo of it?

I'll take a pic and send...thanks for the quick feedback. Getting the dreaded 1128. Last time, techron seemed to fix it. No luck this time. Thinking I can clean the MAF...

[wazoo]

Do you have a photo of it?

Attached a few photos...it's a soft rubber boot...there didn't seem a way to unsnap anything short of unscrewing torx and pulling entire unit out.

[Loren]

So those little tabs sticking out on the sides don't push in or pull out?

[wazoo]

So those little tabs sticking out on the sides don't push in or pull out?

That's what I thought too...but they don't seem functional. I've tried gently pushing, squeezing, pulling. Price to replace is around $300 for a new MAF? Was afraid to break it. Once I had removed the entire unit, I still didn't see a disconnect point. It looked more like a single piece? Beyond my abilities! But then...I'm a simple man....

Wonder if anyone else with a 2000 MY C4 has had this experience?

:beer:

[Richard Hamilton]

I just had the same problem on my brother's 2000 C4. See the attached. The button is on the underside.

C4_MAF.pdf

Edited January 20, 2006 by Richard Hamilton

[wazoo]

I just had the same problem on my brother's 2000 C4. See the attached. The button is on the underside.

Wow, I fiddled with that thing and could feel it underneath...why on earth would someone design the clip so the button isn't visible? :cursing:

I had cleared the CEL and all has been well the last few weeks. Tonight, pulling into the garage, it came on again. Wasn't my day today. Thanks for the info.

[siddharth]

I just had the same problem on my brother's 2000 C4. See the attached. The button is on the underside.

Wow, I fiddled with that thing and could feel it underneath...why on earth would someone design the clip so the button isn't visible? :cursing:

I had cleared the CEL and all has been well the last few weeks. Tonight, pulling into the garage, it came on again. Wasn't my day today. Thanks for the info.

How do you clear the CEL light ? I don't have a ODB2 reader (yet) and was wondering if disconnecting the battery would work ?

Also, any recommendations on a good ODB2 reader ?

:cheers:

Sid

[Loren]

How do you clear the CEL light ? I don't have a ODB2 reader (yet) and was wondering if disconnecting the battery would work ?

Yes, that will work but you won't know what the problem is and it won't correct the problem. Autozone will read your code for free.

Also, any recommendations on a good ODB2 reader ?

Upper right corner of the page click on "Reviews"

[siddharth]

How do you clear the CEL light ? I don't have a OBD2 reader (yet) and was wondering if disconnecting the battery would work ?

Yes, that will work but you won't know what the problem is and it won't correct the problem. Autozone will read your code for free.

Also, any recommendations on a good OBD2 reader ?

Upper right corner of the page click on "Reviews"

Oh man ... I paid the local porsche dealership $110 to tell me what the code means ("diagnosis charge") ... I literally paid for my ignorance :eek:

So Loren, do I have to tell Autozone anything for that free readout ? Just for future references, till I get the OBD 2 reader. BTW, I still don't know the actual error code, but the service guy told me "you need a new mass air flow sensor" (among other things). I'll ask him for the exact error codes tomorrow to make a more informed decision...

About the OBD 2 reader, it looks like the carcode is highly recommended. I guess I'll go for that one then. I'm just surprised how primitive their website is ... at least compared to how great their software has been rated ....

Thanks guys, I'll hopefully know the error codes tomorrow (for $110 ... where is the crying 'smiley' !?!)

Sid

Edited March 1, 2006 by siddharth

[wazoo]

How do you clear the CEL light ? I don't have a OBD2 reader (yet) and was wondering if disconnecting the battery would work ?

Yes, that will work but you won't know what the problem is and it won't correct the problem. Autozone will read your code for free.

Also, any recommendations on a good OBD2 reader ?

Upper right corner of the page click on "Reviews"

Oh man ... I paid the local porsche dealership $110 to tell me what the code means ("diagnosis charge") ... I literally paid for my ignorance :eek:

So Loren, do I have to tell Autozone anything for that free readout ? Just for future references, till I get the OBD 2 reader. BTW, I still don't know the actual error code, but the service guy told me "you need a new mass air flow sensor" (among other things). I'll ask him for the exact error codes tomorrow to make a more informed decision...

About the OBD 2 reader, it looks like the carcode is highly recommended. I guess I'll go for that one then. I'm just surprised how primitive their website is ... at least compared to how great their software has been rated ....

Thanks guys, I'll hopefully know the error codes tomorrow (for $110 ... where is the crying 'smiley' !?!)

Sid

Unfortunately, dealers have to charge for any services they provide...it's how they make a living. I highly recommend you use this as well as other forums to learn about ways to self diagnose if you have the time and inclination. Also, I would not assume that you need a MAF...that is the "easy" assumption. Could be something else as well. I've had a dealer install a MAF only to find that I actually needed to replace a chip. 2 weeks of hassle due to misdiagnosis. Best of luck!

[siddharth]

Unfortunately, dealers have to charge for any services they provide...it's how they make a living. I highly recommend you use this as well as other forums to learn about ways to self diagnose if you have the time and inclination. Also, I would not assume that you need a MAF...that is the "easy" assumption. Could be something else as well. I've had a dealer install a MAF only to find that I actually needed to replace a chip. 2 weeks of hassle due to misdiagnosis. Best of luck!

Which chip did you need to switch ? Also what OBD2 codes did you get at that time ? I got

P1128 and P1130 (rich air/fuel mixture, both cylinder banks). I'm hoping that the MAF cleanup works.

:cheers:

Sid

[wazoo]

Unfortunately, dealers have to charge for any services they provide...it's how they make a living. I highly recommend you use this as well as other forums to learn about ways to self diagnose if you have the time and inclination. Also, I would not assume that you need a MAF...that is the "easy" assumption. Could be something else as well. I've had a dealer install a MAF only to find that I actually needed to replace a chip. 2 weeks of hassle due to misdiagnosis. Best of luck!

Which chip did you need to switch ? Also what OBD2 codes did you get at that time ? I got

P1128 and P1130 (rich air/fuel mixture, both cylinder banks). I'm hoping that the MAF cleanup works.

:cheers:

Sid

The chip in question was for an '87 Targa. I had an aftermarket MAF on it and the shop said the hesitation was due to the "junk" aftermarket MAF hot film sensor. They put on the OE airbox...except...that didn't fix the problem...and billed me $600. Eventually I was able to diagnose this, with help of Autothority, as a faulty chip. Got a new chip and bingo...no problem. Then...asked the shop back for their money and returned their OE airbox. It was a nightmare...but I did resolve it!

Now...regarding the code...I did get the P1128. I cleaned the MAF and used Techron and that resolved the issue...for now. The sad part of this story is that tomorrow will be my last day with that C4. I'll be driving an Audi S4 instead...kids are too big for the backseats...

:(

[siddharth]

Unfortunately, dealers have to charge for any services they provide...it's how they make a living. I highly recommend you use this as well as other forums to learn about ways to self diagnose if you have the time and inclination. Also, I would not assume that you need a MAF...that is the "easy" assumption. Could be something else as well. I've had a dealer install a MAF only to find that I actually needed to replace a chip. 2 weeks of hassle due to misdiagnosis. Best of luck!

Which chip did you need to switch ? Also what OBD2 codes did you get at that time ? I got

P1128 and P1130 (rich air/fuel mixture, both cylinder banks). I'm hoping that the MAF cleanup works.

:cheers:

Sid

The chip in question was for an '87 Targa. I had an aftermarket MAF on it and the shop said the hesitation was due to the "junk" aftermarket MAF hot film sensor. They put on the OE airbox...except...that didn't fix the problem...and billed me $600. Eventually I was able to diagnose this, with help of Autothority, as a faulty chip. Got a new chip and bingo...no problem. Then...asked the shop back for their money and returned their OE airbox. It was a nightmare...but I did resolve it!

Now...regarding the code...I did get the P1128. I cleaned the MAF and used Techron and that resolved the issue...for now. The sad part of this story is that tomorrow will be my last day with that C4. I'll be driving an Audi S4 instead...kids are too big for the backseats...

:(

I cleaned the MAF yesterday. I bought the T20 head with a hole in the middle "tamper resistant toric heads" and an electrical contact cleaner, solvent based and no-residue type. You can find these things at autozone or any other shop. Be careful in picking up the right contact cleaner - I almost picked up a electrical grease cleaner right next to the electroNIC contact cleaner (which is what I want). I can't recall the name but its red and white and has a car electrical socket picture on the can.

So anyway, I disconnected the battery, removed the MAF and sprayed the cleaner on the back side where I saw a 'resistor like' sensor. Thinking of it, I didn't really clean the film in the gap, on the other side where the resistor thing was. So maybe I didn't do a complete job of it. I guess I'll just spray the cleaner all over the whole thing today too. Didn't have the CEL come up, but its just been a day.

I was thinking of also checking the air filter and the air box as such. I unscrewed all the screws around the air box but the air box cover didn't want to get off. It seemed like I was missing something. Any instructions on how to open the air box and examine the air filter ?

Sid

[siddharth]

I cleaned the MAF yesterday. I bought the T20 head with a hole in the middle "tamper resistant toric heads" and an electrical contact cleaner, solvent based and no-residue type. You can find these things at autozone or any other shop. Be careful in picking up the right contact cleaner - I almost picked up a electrical grease cleaner right next to the electroNIC contact cleaner (which is what I want). I can't recall the name but its red and white and has a car electrical socket picture on the can.

So anyway, I disconnected the battery, removed the MAF and sprayed the cleaner on the back side where I saw a 'resistor like' sensor. Thinking of it, I didn't really clean the film in the gap, on the other side where the resistor thing was. So maybe I didn't do a complete job of it. I guess I'll just spray the cleaner all over the whole thing today too. Didn't have the CEL come up, but its just been a day.

I was thinking of also checking the air filter and the air box as such. I unscrewed all the screws around the air box but the air box cover didn't want to get off. It seemed like I was missing something. Any instructions on how to open the air box and examine the air filter ?

Sid

Well, I thought I'd post again with some updates.

So I removed the MAF the next day and sprayed the electric solvent-based cleaner all over the MAF. I sprayed the same resistor-like thing sprayed just the previous day and also into a square section which seemed to house some film like stuff. I basically soaked the whole thing with the spray and let it dry in 10-15 seconds.

I also cleaned the airbox (it was quite clean) and also cleaned the throttle body (also clean). I didn't need to but since I was "there" I did the cleanup.

Now for the screwup ... In my excitement to hurry up (with girlfriend nagging about not making it to dinner) I forgot to connect the electrical connection back to the MAF :oops: . Initially the car felt lethargic but after 10 minutes I needed full throttle to even move the car ! After dinner, it just died off but I restarted it and limped back home. I was quite worried !

At home I saw I had forgotten to connect the MAF so the car computer started using a very conservating air/fuel map. Doh !!! I simply connected it immediately, reset the computer (disconnect battery for 5 minutes). The car seemed energetic - like just before the CEL came up.

I'm just glad none of the belts ate my electrical wires ... it was dangling 5" away from all that and would have been disaster !

All that was over a month back.

Bottom line :

1) Its been a month of hard driving since the CEL (OBD2 code = with O2 sensors) and it hasn't come again

2) The solvent method seems to really work !

3) NEVER do repairs in a hurry - better to do them later when you get some time.

:thumbup: to the solvent cleaning method !

:cheers:

Sid

[NT_996]

Local OPC have diagnosed my MAF as faulty.

I'll try cleaning it first as this thead suggests, but, and my reason for posting, is that the dealer has advised that the new MAF needs "calibrating" (this was from one of the service staff, NOT a technician).

Now, is he simply trying to justify their charge of £400+ for the job, ("sir, we have to get in your car, drive it in to the service bay, leave it several hours to cool down, open the engine compartment, lean in, disconnect & unscrew the old unit, open the packaging to the new one, etc, etc.....") or, is there in fact some truth in the vague statement that "calibration" is required?

Will I also have to disconnect the battery to clear "something" out?

If so, what will this achieve (i.e what is the "something" that I'm clearing out) , and what happens if I DON'T disconnect the battery?

Thanks.

Edited April 6, 2006 by NT_996

[1999Porsche911]

Local OPC have diagnosed my MAF as faulty.

I'll try cleaning it first as this thead suggests, but, and my reason for posting, is that the dealer has advised that the new MAF needs "calibrating" (this was from one of the service staff, NOT a technician).

Now, is he simply trying to justify their charge of £400+ for the job, ("sir, we have to get in your car, drive it in to the service bay, leave it several hours to cool down, open the engine compartment, lean in, disconnect & unscrew the old unit, open the packaging to the new one, etc, etc.....") or, is there in fact some truth in the vague statement that "calibration" is required?

Will I also have to disconnect the battery to clear "something" out?

If so, what will this achieve (i.e what is the "something" that I'm clearing out) , and what happens if I DON'T disconnect the battery?

Thanks.

Just another attempt to rip off a customer. Now you know not to trust this guy in the future. Unless you have a CEL, the is no need to reset the computer by disconnecting the battery. Either way, it will take a few drive cycles for the computer to adjust to the new MAF. Take your wife to dinner on the money you save. You can get a new MAF online for less than $250.

[Loren]

Local OPC have diagnosed my MAF as faulty.

I'll try cleaning it first as this thead suggests, but, and my reason for posting, is that the dealer has advised that the new MAF needs "calibrating" (this was from one of the service staff, NOT a technician).

Now, is he simply trying to justify their charge of £400+ for the job, ("sir, we have to get in your car, drive it in to the service bay, leave it several hours to cool down, open the engine compartment, lean in, disconnect & unscrew the old unit, open the packaging to the new one, etc, etc.....") or, is there in fact some truth in the vague statement that "calibration" is required?

Will I also have to disconnect the battery to clear "something" out?

If so, what will this achieve (i.e what is the "something" that I'm clearing out) , and what happens if I DON'T disconnect the battery?

Thanks.

Only the non-egas cars need to have the DME re-programmed when changing the MAF. That is because the MAF used on the early (C2) non-egas cars is no longer made. To use the newer MAF the DME needs to be re-programmed.

Since you have a C4 - you have egas and there should be no need to re-program the DME.

Perhaps your OPC was confused and thought your car was a C2.

[1999Porsche911]

Local OPC have diagnosed my MAF as faulty.

I'll try cleaning it first as this thead suggests, but, and my reason for posting, is that the dealer has advised that the new MAF needs "calibrating" (this was from one of the service staff, NOT a technician).

Now, is he simply trying to justify their charge of £400+ for the job, ("sir, we have to get in your car, drive it in to the service bay, leave it several hours to cool down, open the engine compartment, lean in, disconnect & unscrew the old unit, open the packaging to the new one, etc, etc.....") or, is there in fact some truth in the vague statement that "calibration" is required?

Will I also have to disconnect the battery to clear "something" out?

If so, what will this achieve (i.e what is the "something" that I'm clearing out) , and what happens if I DON'T disconnect the battery?

Thanks.

Only the non-egas cars need to have the DME re-programmed when changing the MAF. That is because the MAF used on the early (C2) non-egas cars is no longer made. To use the newer MAF the DME needs to be re-programmed.

Since you have a C4 - you have egas and there should be no need to re-program the DME.

Perhaps your OPC was confused and thought your car was a C2.

Loren, the original part number for the 99 C2 is still available. They are not superceded and do not need calibration. Part number 996 606 123 00 whereas the egas for the 3.4 is 996 606 124 00. You can get the Bosch part from an after market supplier or from the dealer. Same part number as is my orginal MAF with a March 1998 build date.

Edited April 6, 2006 by 1999Porsche911

[wazoo]

Local OPC have diagnosed my MAF as faulty.

I'll try cleaning it first as this thead suggests, but, and my reason for posting, is that the dealer has advised that the new MAF needs "calibrating" (this was from one of the service staff, NOT a technician).

Now, is he simply trying to justify their charge of £400+ for the job, ("sir, we have to get in your car, drive it in to the service bay, leave it several hours to cool down, open the engine compartment, lean in, disconnect & unscrew the old unit, open the packaging to the new one, etc, etc.....") or, is there in fact some truth in the vague statement that "calibration" is required?

Will I also have to disconnect the battery to clear "something" out?

If so, what will this achieve (i.e what is the "something" that I'm clearing out) , and what happens if I DON'T disconnect the battery?

Thanks.

Only the non-egas cars need to have the DME re-programmed when changing the MAF. That is because the MAF used on the early (C2) non-egas cars is no longer made. To use the newer MAF the DME needs to be re-programmed.

Since you have a C4 - you have egas and there should be no need to re-program the DME.

Perhaps your OPC was confused and thought your car was a C2.

Loren, the original part number for the 99 C2 is still available. They are not superceded and do not need calibration. Part number 996 606 123 00 whereas the egas for the 3.4 is 996 606 124 00. You can get the Bosch part from an after market supplier or from the dealer. Same part number as is my orginal MAF with a March 1998 build date.

I didn't think these needed to reprogrammed either. Also, what tech. can't tell the difference between a C2 and C4? Sounds like a slow day in the shop...I've had my share of honest mistakes (read up in my thread on the 'problems' with my 87 Targa and aftermarket MAF that turned out to be a fault chip) and ripoffs. Seems it is too easy for unscrupulous techs/shop supervisors to "hang parts" instead of fix problems.

I think shops would be well advised to explain that once you drive a 911 in, they need to get at least $200 in repairs or they don't break even. You have to pay for the tech, the overhead and the parts sitting in the parts bin.

[Loren]

My mistake - 996.606.123.00 is still available. The 996.606.124.00 can be replaced with the 996.606.125.01 provided the DME is updated.

[NT_996]

My mistake - 996.606.123.00 is still available. The 996.606.124.00 can be replaced with the 996.606.125.01 provided the DME is updated.

Thanks Guys.

Loren - I have removed my MAF and it is 996.606.124.00.

If I need to replace it (I'll order a replacement from somewhere such as www.eurocarparts.co.uk), and end up with 996.606.125.01, how do I update the DME?

[currently waiting the results of cleaning]

Regards, Neil.