Another O2 sensor saga...
 

97' Base, 104K, Tip.

June 3rd,
CEL light comes on. Durametric shows-
P0420, P1102, & P1107.

I repalce the 2 pre cat O2 sensors, which I had planned on doing anyway as maintenance.
Reset codes, drive 75miles with no CEL. Just as I arrive home CEL light back on.


Now I have P1115 & P1119 ( heating power ahaed of Cats on both banks.
Feeling a little helpless at this point I take car to local Porsche shop. After $515 of diagnostic labor, they say the 2 O2 sensors are NG, and that there are a lot of counterfeits out there, and I probably got 2... I am skeptical but trust these guys. I'm attaching receipt with notes from shop.

I buy 2 more sensors from a different source and install them. Reset fault codes. Go for another 50 mile drive and by the time I am home the CEL light is back on. Now back to P1102 & P1107 again.
( O2S heating power ahead of cat on both banks exceeds limit value.)

I have to solve this w/o spending another $500 in diagnostics. Electrical issues not my forte, and I fear something crazy in the harness at this point.

MAF sensor? Vacum leak? Any thoughts and suggestions deeply appreciated.


http://986forum.com/forums/uploads02...1721869421.jpg

Which brand of oxygen sensors did you purchase?

P1102 and 1107 indicate the heating resistance of the sensors is too low. Disconnect the O2 sensor harness connector and check the resistance between pins 1 and 2 on the sensor, you should see 1.8 to 2.5 ohms at room temperature. If you get those values, your harness from the sensor to the DME has a wiring issue.

Hey JFP, I was hoping you'd pipe in. Thank you for your expertise. I will check those values tomorrow and report back.

They are Bosche 13806 O2 sensors with the Porsche connector.

Exactly what O2 sensors are you buying? Porsche brand from a dealer? Bosch? Part numbers please.

Bosch 13806, from FCP Euro.

Disconnected sensor, and I'm seeing values closer to 2.7-3 ohms on pins 1 & 2, which on my sensor are the 2 white wires, the heating wires as best as I could determine.

Are you still thinking sensor harness point to DME as the culprit, and if so how would I proceed?

Thanks, Rick

You need the wires that go to those pins traced back to the DME harness pins, looking continuity, shorts, or breaks.

Could be above my pay grade, but I will give it a shot. Thanks Jeff.