ESL

I got the dreaded check engine light yesterday. 20500 miles. I rescued a garage queen 2 years ago. Anyhow, when I bought the car to my local independant he pulled the codes which he said were "10 which is the O2 sensor prior to the catalytic converter" and "13 which is the heat element in the O2 sensor". He claims that by replacing the O2 sensors the problem will be solved because it's the heaters inside which are bad. So my questions are:
1) Does this sound resonable or is this BS? (I think the latter).
2) How can I tell if the "carbon issue" has reared it's ugly head?
3) Any other suggestions?

There is a ton of info here, I just haven't seen this take on the problem here in the 150-200 posts I've read since yesterday am.

BTW, the dealer claims to have seen it in 996's but not 993's.

Thanks all,
Eric

viperbob

Eric,

In the Posche OBD2 manual, there are like 8 codes (they will also tell you which bank of cylinders so you can get the correct O2 sensor as there are two) that deal with O2 before cat issues and 4 other codes for heater issues on the sensor before the cat. Not sure on the codes your mechanic is describing. What kind of scanner they are using? The real codes are more like P0132 and P1105. As I mentioned, the proper codes will isolate it down to the individual O2 sensor. Sounds like they are on the right track though...

SundayDriver

Independently of the problem, you really need to find a service shop you can trust. I guess you don't trust the dealer so you went to an Indy but think his assesment is BS? Keep looking till you find someone you like.

As far as the O2 sensor, he is proably right. The codes are telling you exactly what is happening. The particular O2 sensor that is a problem and what the problem is. The O2 sensor heater is not working correctly. O2 sensors have a limited life and it is very common for cars as old as 993's to have them go bad. They will fail either in the sensing element or the heater. Sounds to me like the Indy knows what he is talking about.

ESL

Thanks for the quick replies. I guess I am a cynical fatalist and have probably too much info in my brain of the worst that can happen. I was assuming it would be the carbon buildup problem and when their diagnosis did not correlate with mine I decided I probably knew more. Thanks for helping me extricate my cranium from my anus!

Steb

I'm also getting a CEL everytime the gas reserve light goes on. The dealer said it was a code related to a sensor in the gas tank and then reseted it. Any ideas what might be wrong?

Thank you.

Lorenfb

You really need to have your tech provide the actual DTCs numbers.
Then have the codes reset and drive it until the CEL comes on again.
Re-read the DTCs again to verify that no "false" codes have occurred
before spending any money. OBDII problems can get very expensive
if there're mis-diagnosed.

"I'm also getting a CEL everytime the gas reserve light goes on. The dealer said it was a code related to a sensor in the gas tank and then reseted it. Any ideas what might be wrong?"

This DTC probably results from from a gas tank leak or a bad tank pressure sensor used by the OBDII system for the EVAP test.

Steb

Thanks for the heads up Loren, I'll take it to the shop this week to have the codes reset (and get the DTC numbers).

Cheers,
Esteban

993inNC

E.
find your way to an Autozone, let them read and print the codes for you for free, unless you really trust your shop and he won't charge you to much to read 'em By the way, they can shut that damn light off too

ESL

Amazing this popped up again after nearly 3 months. My CEL went off by itself!! I guess, according to the shop, if there are no errors in 5 successive on-off cycles the light automatically resets?! So far, 2 months and 3K miles without the light.
She's away for the winter (1 inch of snow and they salted ). Hopefully I dodged the bullet for now.
Thanks to all!

Steb

Hey Chris, thanks for the tip. No Autozone nearby but I went to Schuck's (got to give them proper credit), they were very friendly and helpful. The real funny thing is that on my way to the store the light suddenly goes off (at least after 20 or more on-off cycles). The scanner shows a P0441 freeze code, "evaporative emission control system incorrect purge flow", which apparently might be caused by the gas cap not closing properly. At least it's consistent with the explanation from the dealer when I got the CEL for the first time, so I just bought a new cap, had the code reset and will see how things go.

993inNC

Steb,
Good luck, wish mine was that simple. Mine code is the 0410, SAI on the 1-3cyl bank. I just got this car recently and need to do an oil change as well as V.cover gaskets so I can get back to square 1. Maybe I'll get lucky and it won't consume excessive oil (valve guides).....A boy can hope can't he