Cel

[rk1234567]

1999 Boxster 25K miles from new. The cel light came on a few weeks ago almost immediately after I put gas in it. I took it to the Porsche dealer I bought it from, he reset it but said I was getting close to needing 4 new oxygen sensors, $800. I called another Porsche dealer & he told me that was BS! I put gas in yesterday & the lights back on an hour or so later. I am thinking a bad gas cap. Any ideas?

[vath2001]

Change the gas cap. its cheaper than the O2 sensors. Did the dealers tell you what the codes are? It may be worth the money to get a OBD2 code reader.

And just for reference... my CEL is been on for 6 months. I read the codes and checked the forums... its emmisions stuff.

Sign up to http://www.renntech.org
to get the codes.

Welcome.

[Log]

Take your car to Autozone, or Advance. They'll scan the cel code for free.

[Brucelee]

Originally Posted by vath2001

Change the gas cap. its cheaper than the O2 sensors. Did the dealers tell you what the codes are? It may be worth the money to get a OBD2 code reader.

And just for reference... my CEL is been on for 6 months. I read the codes and checked the forums... its emmisions stuff.

Sign up to http://www.renntech.org
to get the codes.

Welcome.

You might want to attend to this emissions stuff anyway.

In the long run, it can't be good for your car or my air.

[vath2001]

I have a problem with the secondary air pump. Which means that the valve or switch are bad, and the air pump can not dump extra air into the exhaust allowing the car to pass emmisions tests when the engine and Cats are cold. So my car doesn't "cheat" right now.

The air is still safe. And I will correct the problem, its just not a priority right now.

[rk1234567]

Got gas & replaced the gas cap, code was p1123. Drove around for a while, CEL is still on.

[Noboarders]

I had the same proble when I got mine. My mechanic checked it out and sure enough, its MAF sensor. I got it replaced and problem solved.

If you run with bad MAF sensor, gas consumption will increase and power as well.

[rk1234567]

Is the MAF the same as oxygen sensor?

[rk1234567]

Seems to be a different code to mine,
P1123 Oxygen Sensing Adaptation Area 1 (Cylinders 1 - 3) - Lean Threshold



P0101 Mass Air Flow Sensor

[fatmike]

These are pretty common repairs on Boxsters (and any 9 year old car).

I'm not an expert, but:

The MAF = the "mass air flow" sensor. Its a sensor that sits right behind the air intake behind the driver. You can easily change that yourself it you buy the right type of socket wrench. Hardest part about this job is access to the engine bay -- but the MAF is right on top. You can also clean the MAF, NAPA sells "MAF cleaner". Cleaning has to be done right though.

The "oxygen sensors" are sensors that plug into the exhaust. If you look under the car, they pop into the exhaust system (before and after the catalytic converters) and they have a 6" wire with a plug on the end. Also a do-it-yourself job that is roughly as complex as changing your oil. Hardest part with this is getting under the car and "finding" the sensors. You can change 'em in :30 seconds each.

The MAF tells the engine computer how much fresh air is coming in. The oxygen sensors tell how well the gas and air are being burned in the engine. Together they tell the engine computer how to adjust fuel and air to optimize performance and tune. If the MAF or O2 sensors give bad readings, the car can run rich or lean, resulting in loss of fuel economy, poor idle, loss of power, clogged spark plugs, etc.

I'd suggest running a bottle of TECHRON thru your gas. Read and follow the label directions. After you do that run a full tank of gas (or two) thru. Then change the oil. Techron will clean system out (and dirty your oil). Reset your CEL and see what happens.

If the CEL doesn't go away, you can take the car to someone who can diagnose which bank of O2 sensors (or maybe its just the MAF). Another option is skip all the fretting and diagnostics, change the spark plugs, MAF and O2 sensors and I bet your car will run like a champ for the next 30K miles...

Good luck with it.

[turbo23dog]

In my wife's BMW, I used to leave the ignition key in the on position to keep the radio for the wife while I was out pumping the gas. The BMW's computer checks for vacuum breaks in the fuel system on a sked of every 5-10 minutes or so. One day after filling up, the CEL popped on as we left the gas station and I'm thinking damm whats's wrong. We found afterward that if the computer checks for vacuum break while the gas cap is off, well thats a major leak that triggers the CEL. So I always take the key out of the ignition when filling up, just to be safe. I have no idea if this applies to Boxsters but its something I always follow in all my cars anyway.