CEL goes on and off

[rychone]

I have a MY2000 996 with 30k miles. My CEL turns on and then off after a few drive cycles. It has been doing this for a month. The codes i get are P0139, P0140, and P0446.

I would like to try and replace the O2 sensor to get rid of the error codes P0139 and P0140. I believe this is the O2 sensor after the catalyst on the drivers side but can someone confirm this? And is there anything else i should check for? Also, are the aftermarket O2 sensors any better/worse than the Porsche genuine O2 sensors?

I'm going to replace the gas cap and see if that fixes the P0446 code. What else can i check for before having to go into the shop?

Thanks...

[1999Porsche911]

I would first check the wiring for the o2 sesnors. You may have a pinched wire causing them not to heat up fast enough.

[ToblertheDog]

rychone,

I agree with 1999Porsche911 regarding the "...check the wiring for the o2 sesnors" recommendaations....espepcially if your getting a P0140 fault. Could simply be bad wiring.

[rychone]

Thanks guys... I'll check the wiring.