Mass Air Flow Sensor /Check Engine Light

CEL came on when I accidentally fueled with engine running. Dealer tells me I need a new MAF sensor...estimate of just over $500. Advice? How easy to install on my own? I understand it's quite easy. What about cleaning? Has anyone tried that.... The 2000 C4 is my daily driver... Appreciate any help!

I need one too....Mine has come on and off for a while now......

Why would the CEL light come on for the MAF with the engine running and adding gas? I think you better take the car to another shop as it sounds like "snake oil" to me. The MAF and gas tank are not interrelated. I just don't see how could this ruin a MAF. The new OBDII cars can sense if the ventilation/evaporator system errors in the gas tank and fueling with the car running would set it off. Have the memory cleared from the ECU and see if the CEL turns on again. I bet the dealer is just trying to get you for something. The MAF is easy to change. All it takes is to remove it from the air box top and unplug it.

Ask for a description of the fault code. It sounds to me like your car detected a leak in the evap system (your gas cap being off) and set a fault code. I would request the code to be cleared and continue driving (with the gas cap tight!)

Check out Renntech.org. Loren has a great tech and DIY site set up. I am sure several MAF's have been replaced and documented over there.

Never, ever take the word of a Porsche Mechanic. The are nothing but parts replacers. If they read the code, have them show you the OBD printout, then you lookup the code and it's meaning yourself. The MAF does not just go out all of a sudden without you noticing engine probelms. If the car is running fine, then it is not the MAF. Reset the computer by disconnecting the battery for a few minutes and see if the CEL comes back on again. Even if you do not reset the computer, if it was caused by the gas cap being loose, the CEL will go off after a few drive cycles. Remember, few Porsche Mechanics know anything about the sensors in these cars. If it doesn't tell them exactly what to do in the repair manual, they simply start replacing parts at your expense and inconvenience.

Totally agreed. I had my check engine light come on and code indicating it was the MAF sensor, but everything was running fine, so he reset it and it has not come on since. Don't jump to the gun just yet...

where can i look up what the code means? I just had my MAF sensor replaced because the CEL came on.. but low and behold.. two weeks later it's back. So I assume it's not the MAF. TIA

what code is it? YOu can look it up here: http://www.renntech.org/forums/index...pcode&code=dme

I hate to say this but it really sounds as though your dealer is blowing smoke up your tailpipe! I'll bet you probably went into the dealer's service department where you were met by a person who wears a necktie and maybe has a little 'automotive experience. Do you really trust a service writer to convey your car's problem to someone else...why cant you speak directly to a Porsche "mechanic" at the dealership? and have you ever noticed that service writers know everything there is to know about P/cars. The last place my friend that you ever want to take your Porsche to is a porsche dealer. Ask around and find the best independent shop in the area and GET TO KNOW THEM VERY WELL! So when you have a problem you talk directly to the mechanic not a "service advisor". At a Porsche dealership there are no such things as "Porsche Mechanics". Porsche dealers employ "Porsche Part Changers" and they charge you a 100 bucks an hour for their "special skills"... The MAF part alone is 290.00 at Porsche and my understanding is that there is a Bosche MAF available. Check around for the Bosche part. It takes less than 10 minutes to replace MAF and the only special tool you need is a "secuirty" torx. You can get a complete set at Sears or any good parts store like NAPA for under 25.00. Good luck... J

I agree the MAF sensor measures the airflow as it enters the intake just after the air cleaner. It is could not be damaged by fueling the car while it is running. Maybe it failed at just that moment but I doubt it. Reset the fault and see if it reoccurs.

The other thing is that, unless I'm mistaken, there isn't a code that says the MAF has failed. As I recall, you either get an O2 sensor code or you notice a loss of power when the MAF goes. It's educated guessing on the part of the mechanics. I wouldn't be as hard on dealer mechanics as jcoduto. They have a lot of training and the very best equipment but I would agree that a good independent is usually much better to work.

My dealer said over the phone that it was probably on o2 sensor, not the maf. He said to bring it by and he will read the code and show it to me... I'll let you know the outcome. They seem to be very cautious about seeing people pay for things they do not need. Robert

Are you experiencing any engine problems? If not, just reset the computer and move on with your life.

Dealer checked the faults in the computer today and 2 fault codes came up. 02 sensor and one they said they have not seen.....before...They said it could be a loose wire or damaged wire etc... I am bringing it in monday to a local specialist that all the PCA people in San Diego use and trust...........

The dealer should print out the OBD reading for you so you can see ALL the codes and other failures that have happened. DO NOT go in blind to a dealer. Like I saide before, just reset the damn computer and it probably will never come on again. If your car is running fine, then there is not a sensor problem.

Thanks...How do you reset the computer? Is it a DIY?

Simply disconnect the negative ground from the battery for a few minutes and then reconnect. Make sure you have your radio code available as you will have to enter it in the radio when you turn it on. Then start the car and take it for a drive. The car may stumble a few times - until the computer learns the program again. You may have a slightly high and varying idle (800 - 1100 rpm) for the first 2 or 3 times you start your car, but that is normal and after a few drive cycles the computer will completely learn and the car will run smoothly again.

I dont understand why people place all this trust in independent mechanics. Independent shops dont even have the proper tools to work on these cars. No one here can say for sure what this guys car needs because no one here has actually seen the fault codes in his DME. He mentioned he had an "02 fault" as per his post which could be an o2 sensing fault which is very commom when these MAFs start to go bad and give false air mass readings. I like this board because we can discuss these cars but people go to far and speak about information they dont know and with experience they dont have. Even if we knew the fault codes stored in his DME it is not possible to tell %100 what exactly is wrong with his car. Sorry people but you can not diagnose a check engine light over the internet. We can steer him in the right direction but that's exactly where our power ends.

The dealer and the porsche "independent" said that they would need to diagnose these problems in depth and that the fault codes are only a starting point etc. I am basing my information on experienced porsche people who have had a number of cars for a long time serviced at this shop. I understand that the dealer and these shops are only as good as their mechanics, experience and equipment. This dealer has been good to me in the past but I just want an opinion from another source before spending some money... Thx for the input.

PTEC, He asked a question and people are answering to the best of their ability, ultimately it's Robert's responsibility as it is your's and mine when asking a question, as to what decision to make. Based on your post each question of this type should only produce one answer "Take it to your dealer and let them tell you." That defeats the purpose of having everyone else's experiences as a database from where you can get an idea as to what it could be. Robert, When you first posted the issue, I thought it could be an O2 sensor, as I've this happen before in one of other cars (BMW M3). However after reading your follow up posts I'm almost certain that an O2 sensor is it, please make sure the dealer gives you the print out because I can't see how a wiring issue may arise from refueling with the engine on, unless it was strictly coincidental, but what are the odds??? Just my $.02

As I said in my post, discussion is great. I also said we can steer him in the right direction (aka "get an idea as to what it could be). We can all speculate what his problem is but the truth is nobody here knows for sure what the cause really is. My point is that people shouldnt come on here and say "Oh it was just a code from your gas cap, unplug the battery and keep driving."

PTEC, Your generalization of independents is not true. "I dont understand why people place all this trust in independent mechanics. Independent shops dont even have the proper tools to work on these cars. " We are an independent, have been in business for 28 years working on Porsche exclusively. Avg. years experience of my techs, 25 years each on Porsche. Yes, I have spent the thousands of dollars on Porsche Systems Tester, additional software, all factory manuals, and specialized tooling. We have many customers that would prefer us to take care of warranty work and pay us becuase we able to take of the problem in a timely fashion and we know what we are doing. Sorry if you had bad experience with an independent but if you have been around this board long, You should have seen the comments about bad experiences with SOME dealerships. Laura Hergesheimer MotorSports www.hergesheimer.com

Any good independent shops in Tampa, Jacksonville, or Orlando?

I had a series of CEL warnings, finally got sorted after the Independent took the Car to an OPC to have the fault codes read out and reset As a sweeping generalisation, OPCs tend to replace things, Independents tend to fix things - you pays yer money and takes yer choice. Sooner or later, it would be better to check the OBC readout and verified. Koenig