I have a 2009 Carerra S, engine light just came on with 54k miles. I ran OBDII and the code came back Confirmed:P2415 02 Sensor Exhaust sample Error; Pending:P2415 O2 Sensor Exhaust Sample Error; P0174 System too Lean; Permanent: P2415 02 Sensor Exhaust Sample Error. It looks like O2 Sensor 1 showing 0 Volts, 02 Sensor 2 showing 0,41 Volts. Looking for advise as to which sensor this is before the CAT or after the CAT. I think it is the passenger side with the Blue Cable. Anyone with advise on changing sensor from experience. Also is there any issue with cancelling the fault code before or after replacement. Thank you.

 

With my Boxster and 996 Turbo the factory OBD2 error details specified which sensor was being flagged. Bank 1 (or 2) and Sensor 1 (before the converter) or Sensor 2 (after the converter).

So, for "O2 Sensor 1 showing 0 Volts" it looks like this refers to the pre converter sensor while "02 Sensor 2 showing 0,41 Volts" refers to the post converter sensor. Now all you need to know is which bank...

Before you replace the sensors but after you have written down the error codes and also after you have retrieved the freeze frame data which is a snap shot of various engine/sensor telemetry at the time the error was logged, along with the specific error code that triggered the capture of freeze frame data and the primary code responsible for the CEL it is "SOP" to clear the codes then road test the car to see which if any codes come back.

For the wrench to remove and tighten the sensors I bought a properly sized open end wrench but one that was designed for use with hydraulic line fittings. The wrench rather than just working on two opposing flats was designed to encircle and engage more than just two flats. The wrench was open ended of course but had a narrow opening with just enough of a gap to allow the wrench to pass the sensor cable.

But some have had good luck with believe it or not a good (Snap On for instance) brand of adjustable wrench. You want to be sure you do *not* round the sensor flats or you'll have a heck of a time getting the sensor removed.

To change a sensor or sensors you want to be sure you can first disconnect the sensor from the wiring harness. Some years ago when I went to replace sensors in my Boxster I could not do this. I ended up having to take the car to a dealer service department. The sensor connector can have a latch that needs to be released before the sensor connectors can be separated. To release this latch the connectors may have to be pushed together a bit to release the pressure on the latch so it can open fully. I could just not get my hands into the right/best position to do this laying on my back under the car with the car on Rhino Ramps.

Handle the new (and old) sensors with extreme care. (The old sensors may be ok.)

Avoid static discharge to the tip or to the sensor electrical connector or to the wiring harness connector.

For either sensor you do *not* want to touch its tip. Do *not* apply anti-seize or really anything the threads. When I bought Porsche O2 sensors they came out of the box with the threads coated with a very light coating of and light colored grease. When I bought a pair of OEM O2 sensors the sensor threads were "dry".

Do *not* use any cleaner on the new sensor. (The old sensor will not benefit from any cleaner so don't waste your time.)

Use *no* electrical cleaner at the wiring harness connector.. Some O2 sensors "breathe" via the sheathed wire lead from the sensor to the wiring connector and if you spray any cleaner into even the wiring harness connector this can foul the sensor. The sensor must have access to outside air in order to generate the electrical signal that represents the amount of or lack of oxygen in the exhaust gas stream.

 

Thank you very much for the tips!