2000 996 Recurring Check Engine Light

Joe K · 08-22-2010, 07:19 AM

I just bought a 2000 Porsche Carrera. After the first day in my possession the check engine light came on steady while driving. I took it to a factory trained tech in a Porsche dealership and he diagnosed it to be from the fuel/air mixture. The Porsche tech took forever to determine that the check engine light was supposedly being caused by a bad mass air flow sensor. So, $1100 later I got my car back from the shop with a new mass air flow sensor. The next day home, after driving it for 50 miles, the check engine light came back on steady again with no noticeable change in performance, just like before. What on earth could be causing this? I'm starting to think that the previous owner got rid of this car because of this recurring problem that maybe no one could fix. The car has only 58,000 miles from one previous owner. I got the car thru an auction so I don't have access to the previous owner or any of the car's maintenance records.

rb101 · 08-22-2010, 10:48 AM

You need to get a code reader and find out what the codes are (most auto part places will do it for you for free). Without codes it's all a guess.

BYprodriver · BYprodriver's Garage

I would go back to the shop that "fixed" it before & get your old mass air sensor back & tell them to try again. It could be a vacum leak & need a smoke machine to find it. The check engine light was probably reset before the auction but will return until the problem is fixed.

racer · 08-23-2010, 09:33 AM

Certainly, for $1100, I would take it back and have it re-examined or ask for your money back.

x2 on the quick "auction fix". Untill ALL the codes are scanned it will just be a guessing game.

mikejansen · 09-02-2010, 07:52 PM

EMISSION CODE....year 99 & 2000 models were famous for this triggering check engine light! It is a system that will only "clear" if the "fault" is fixed. Usually an O2 sensor in the exhaust. Here's the kicker, the guy fixes what he thinks is wrong, "clears" all code faults and it looks good...right. WRONG! The Emission system takes about 2 hours of driving to reset itself, in fact you cannot pass a test at a smog place because it will say "Not all sensors ready". So...the guy cleared your code, but after your 50 miles or so, blink! the check light's back on because the system has reset and the problem still exists! 9 out of 10 times it is the emissions. Get your money back and find a shop that knows how to diagnose porsche emission codes! Cheers!

torontoworker · 09-14-2010, 08:28 AM

You also got screwed on the price *even* if that was the fault. The MAF is anywhere between $200-$300 depending on where you buy it. It takes all of 2 minutes to remove/install. You only require a a set of security hex (central peg in the middle) drivers that I bought locally for $12.00.

9 times out of 10 the MAF is dirty and can be cleaned with a couple of shots of injector cleaner. If he was at the dealer level he used the Porsche tester which would have directed him to the MAF sensor. Dealers remove and replace - not clean and replace. It's how they make their money.

But you got killed on some bogus hourly labor rates here as with the part price, and dianostic. The labor is not more then 1 hour plus the part install - 2 at the most. So lets say the labor rate is $150 and hour and we have a slow guy who takes two hours. There's $300 plus the part cost at at an over charged $300 plus whatever are your local taxes. I figure no more (on the high side) then $700 but should be around $500 if you went to an Indy garage. But $1100.00???? They saw you coming.

You can buy a MAF for a non-Egas 996 for a s little as $215 here (Porsche 996 & Boxster Intake System - Page 2) and you know the dealer gets this part at half this rate - so you figure out what the mark up was on your job!

I'll tell you what he'll say when you go back to him: he'll tell you it's a "new" code! They replace the MAF as the 'default' fix no matter that it can be cleaned or tested. It's a quick turn around and out the door you go with your wallet a lot lighter. A lot of the time they are right, it was the MAF - it was just dirty!! For the returns where it wasn't the MAF they will say well because the MAF was bad - that led to the O2 sensor's going bad so they have to be replaced as well. OMG the scams they play.

Same with gummy crap on the edge of the intake butterfly or in the barrel itself. A quick clean and the idle clears up and stops throwing codes - maybe a shot of injector cleaner into the idle control valve. An indy will try this first but dealers will throw in the $350 ICV and run injector clean up service and it's another $2000 rape_a_thon.

The best scam is when they find your oil fill cap is loose or the O ring is missing from the inside of it and the air is leaking through, which of course will throw a CEL if you drive long enough this way. Then it's open season on your wallet and you'll have no way to tell WHY these codes came up - they will just show you a print out of what they will say are sensors that NEED to be replaced.

Same with gas cap's that are defective or not on tight enough - another CEL. Of course it will show a fuel pressure issue - the gas cap pressure relief valve has failed open. Gas caps are $14.50 on this site. Now of course you'll be told it is a fuel pressure regulator that *needs* to be replaced... considering the labor rate to replace this part - the default setting is ALWAYS the difficult fix and expensive part.

Buy a code reader or if you have a few bucks Durometric software and cable.

Find yourself a good indy in your area - ask fellow P car owners - and then develop a good relationship with them. You'll never go back to a dealer again unless you buy new and have a warranty.

88carrera · 09-14-2010, 10:06 AM

Joe K,
Please give us an update on what you may have found out about this problem.
Thanks.

Laura-Hergesheimer MotorS · 11:28 AM

If you have the proper diagnostic equipment you don't need to drive the car for 2 hrs to find out if the problem is fixed. There are tests you can run with the PWIS or PST that will let you check numbers immediatley to see if the repair was successful or not. I suggest going back to the shop that did the work and give them the chance to fix the problem but no more money. You shouldn't have to pay for them to practice.
The fault codes found should be listed on your paperwork.
The problem can be fixed, CEL are not that difficult.