Cant Find Fuse P0050

[Xtony]

If it was a pre-cat sensor, I feel your pain! Been there and done that. Had to use the old sensor harness to slide the new sensor down from the top and then there's still barely room to get the threads started.

[gregg3gs]

Originally Posted by Xtony

If it was a pre-cat sensor, I feel your pain! Been there and done that. Had to use the old sensor harness to slide the new sensor down from the top and then there's still barely room to get the threads started.

Yes, that pas painful.
Again, wow!, what a genius spot to place the o2 sensor.

[ard]

How did you diagnose it finally?

Did you find the fuse (in case anyone else in the next 10 years is searching.......)

A

[gregg3gs]

To keep it short,
All my testing was comprised of visual inspection and some continuity testing.
I ended up pulling out and visually inspecting almost all fuses (I had no fuse pin-out -> used car)
I believe that fuses related to o2 sensors are located on passenger side in engine compartment and under cabin fresh air intake system, inside ecm box.
I pulled both fuses I found there (believe those to be 40A, inspected them visually and reseated them)
Farther, I looked at all wiring and to the sensor and determined it was not damaged, torn, broken... you get the idea.
A BMW tech, when hearing of the code I had, with certainty said the problem I had was a bad sensor.
I've purchased a replacement Bosh sensor at a local imports place since the price for it was 187 vs. 300 the dealer charges.

Here is the link to Fuse Panel Pin-out: http://www.xoutpost.com/bmw-sav-foru...tml#post942809




Here is what I had to do to replace the o2 sensor (bank 2, sensor 1):

Things to know (terminology and some blah, blah…)
-bank 1 = cylinder 1,2,3,4 or passenger side (black side - connectors are black on all sensors for this side)
-bank 2 = cylinder 5,6,7,8 or driver side (gray side - connectors are gray on all sensors for this side)
-sensor 1 = pre catalyst (catalytic converter) = upstream (in BMW speak) = sensor closest to the engine
-sensor 2 = post catalyst (catalytic converter) = downstream (in BMW speak) = sensor farthest away from the engine

sensor locations
- Bank 1, sensor 1 and sensor 2 are located and visible from under the vehicle on passenger side and from under the passenger seat area (after you remove protective skid plate)
- Bank 2, sensor 1 and 2 are located and visible from under the vehicle on drives side and from under the drive seat area (after you remove protective skid plate)

Another helpful link: BMW Workshop Manuals - X Series E70 X5 4.8i (N62TU) OFFRD Workshop Manual - 3 RA Replacing Left Oxygen Monitor Sensor (N62 _ N62TU)


Work to be performed: (in no way I authorize you to do any of this work. Only a qualified BMW dealer can do this repair and you should let them)

Important: Scolding Hazard! get a Fan and place under the car to cool down the exhaust system before you start any work on it:

Lasko 20 in. 3-Speed Box Fan-3733 at The Home Depot
- put car on ramps
- remove protective skid plate, the last plate located farthest back from the front
(order of skid plates: 1. plastic belly pan/cover; 2. metal oil filter area skid plate; 3. transmission skid plate)
- disconnect o2 sensor you are replacing (you can follow cables from each sensor. Sensor 1 connections are located under passenger seats inside a connector clipped housing)
- remove sensor 2 to allow your arm access to a clip holding cables for sensor 1
- top of engine: disassemble air intake remove two air intakes to air box
- remove top of air box
- remove both lower parts of air box
- remove rain gutter/tray on driver side
- remove center peace connecting drive side rain gutter to passenger side
- remove aluminum cross tie on driver side
- from bellow the vehicle loosen the o2sensor with a long open end wrench (unless you have an o2 wrench)
- find a little boy and place him on top of engine or get thin arms (lol!)
- o2 sensor can be reached from above engine drive side back of engine corner
- replace the sensor
- tighten sensor from bellow
- replace all parts in reverse order
- using an obdII scanner: reset ecm code
- restart the car and make sure everything runs