Questions about O2 sensors...

[papasmurf]

Was driving home the other day and the CEL came on and I did not have my scanner with me so I pulled into an O'reilly's and scanned/cleared the code before proceeding home. The code was 1117 and their scanner did not have the code definitions for porsche so I checked in online when I got home and it seems it is O2 sensor related. I thought it might have been a one time thing but the CEL came on again about 24 hrs later while driving home (both times sitting idle at a light). The car has 79k miles and I am fine with changing out the sensors if needed (was planning on just the pre-cat sensors) but was wondering which model to purchase. I have read through Mike Focke's site at the part numbers and was planning on purchasing the OE Bosch parts without the connector and just splicing connector from my old O2's onto the new parts. I have heard the basic part is the same that Bosch sells and the markup is more for the already configured pigtail/connector that is porsche specific. The part number I am looking at buying is bosch PN# 15738. Have plenty of people used this with success?

[papasmurf]

actually just checked the code definition again and it is the post cast (rear) sensor that is indicated by P1117

[JFP in PA]

Originally Posted by papasmurf

actually just checked the code definition again and it is the post cast (rear) sensor that is indicated by P1117

According to the Porsche OBD II diagnostics manual, P1117 is for the bank 1 sensor ahead of the cat......

[Topless]

+1 JFP
O2 sensor heating is most often a wiring issue (rodent damage, chafe, fried wiring touching aftermarket headers). I am also in the "never splice a sensor" camp. For a few extra bucks you can get sensors that are configured correctly for your car and they are plug-n-play. A few ohms due to resistance in a splice can have significant effects on how the car runs and I have seen way too many poorly spliced sensors that promptly came apart once the exhaust system heated up. A proper O2 sensor splice can be done. I just don't ever see them.

[papasmurf]

wrong from another website (rennlist I think). Evidently someone had the wrong information as well and said it was the rear sensor. I am not fond of splicing connectors as well but from the shopping I have done, the sensor with the connectors is about twice as much as the OE sensor without the connector, neither being the porsche "boxed" part.

[JFP in PA]

Your post is the perfect case for why you should always find out the full definition for a code before you start swapping parts................

P1117 is the code for a problem with the heater circuit on the O2 sensor, but does not necessarily mean that the sensor needs to be changed; it could be a simple wiring or connector issue (very common), or it could be the sensor itself in the worst case scenario. That said, if it is a wiring issue, the new sensor will do the same thing.

Do some online research for the specific code (P1117) for the specific year of your car; you should find a full set of electrical circuit tests (voltage and continuity) that can be done with a $10 multi-meter before you jump (possibly without cause) for a much more expensive part that may or may not fix the problem............

[JFP in PA]

Once you have tested the electrical circuits, and have determined that you actually need to replace the sensor, you may want to check out Mike Focke's website about sources:

oxygensensors - mikefocke2

[papasmurf]

that's where I went earlier to get the part numbers for the bosch branded parts. Great site to have as a resource.