DIY: Repairing an issue related to Throttle, Throttle Body or Wiring Harness P0120, P0121, P0221 Codes. E70 X5 N62 4.8i


Problem: As you drive around all of a sudden car goes into protect mode and reduces power. Eventually, when you pull over, you may observe an erratic behavior from your engine and idle fluctuating from about 800 to 1200 rpm. Obviously you get a bunch of warning icons and your dash lights like a Christmas Tree, a message on your Central Display says “AWD and DSC 4x4 system and DSC have malfunctioned, you gonna have a bad day” (or something to that tune).

- Just lost power in the Accelerator and pulling off to the side of the road Video
http://vid172.photobucket.com/albums...pstqluzd33.mp4
- After pulling off to the side of the road Video
http://vid172.photobucket.com/albums...pszwfzgz4o.mp4

- and some images or aftermath






Eventually you pull over, pull out your OBDII scanner and get these codes:
- P0120 – Throttle Position Sensor (G69): Circuit Malfunction
- P0121 – Throttle Position Sensor (G69): Implausible Signal
- P0221 – Angle Sensor 2 for Throttle (G188): Implausible Signal


Disclaimer: in no way does reading this post authorize you to do this repair yourself. You should always service your BMW at an authorized BMW Service point. Death and injury may/will result if you undertake this repair.


What follows is my experience.
Enjoy.

What you need:



- BMW E70 X5 (my 2008 X5 E70 4.8i, N62), or any BMW 4.8 engine equipped car
- basic tools to include: wire cutters, dikes, flat screwdriver – long, 10mm socket, ohm meter (multi-meter), crocodile clip, pin tester end, heat gun or a lighter
- new parts (not all of these but): Throttle Pedal, Throttle Body, Harness Repair Kit
- OBDII Scanner (almost any scanner will do)

Additional work I’ve performed:
- tested wire harness from six pin connector at Throttle Body to Control Module located under outside cabin filters (no break found)




Things to know:
- this project should take no more then about 45 minutes to perform (and two beers).
- there is no way to test the throttle pedal with an ohm meter
- the issue most likely is a bad wire harness plug pins
- how to reset Throttle Body Adaptation (Memory), also used to reset throttle lag: http://e84.xbimmers.com/forums/showthread.php?t=812743


Parts: (you can get your parts from import auto parts store that is local close to you, https://www.ecstuning.com and http://parts.bmwofsouthatlanta.com/)

- Wire Harness Repair Kit - # 12 51 7 602 973
- Throttle Valve Assembly (throttle body) - # 13 54 7 535 308
- Acceleration/Accelerator Pedal Module - # 35 42 6 859 999


Repair:

I strongly suggest starting this repair with the least costly part

- disconnect battery (located in trunk under the floor cover)




- disconnect MAF sensor


- remove airbox top cover


- remove driver side intake vent

- remove MAF to Throttle Body pipe




- remove filter box driver side (make sure not to loose rubber grommet)
- remove filter box passenger side (make sure not to loose rubber grommet)


- remove air box back bracket, torx bit (located in the back)


- remove driver side airbox post, torx
- disconnect Throttle Body connector at Throttle Body
- remove cover from wire tray, follow Throttle Body connector until you arrive at a plastic tray, you will need a pick or a small hook to unhook all the clips, take your time



- visually verify Throttle Body wiring has no abrasions especially next to the zip ties

Note: I have performed the test of Throttle Body Connector to the Control Module and have not found any problems with wiring. Afterwards I even drove 300 miles until the issue popped up again. Afterwards, when I drove below 75 miles the car would throw codes. When I drove over 80/85 I never saw the issue again.

- unpack the new replacement wire harness and notice it’s length (it will look something like this – this one is the old one I replaced)



- cut wires as to allow for and easy splice and slack
- using tester / multi-meter verify each color coded wire and make appropriate splices (listed below is what my wire harness looked)

OEM COLORs
Pin 1 – Yellow with Blue stripe & Black dots
Pin 2 – Blue
Pin 3 – Yellow with Black stripe
Pin 4 – Yellow with Black dots
Pin 5 – Yellow with Green stripe
Pin 6 – Black with Yellow stripe

Note: In my case I did not splice the wires are pass-through and more of a wire-nut style

- make sure to install shrink wrap provided on all the connections you’ve made

If you were to replace the Throttle Body this is where you do it. All you need is a 10mm socket. All you need to do is undo the four bolts holding the TB in place and reinstall the new unit.

- reconnect electrical connection to the Throttle Body
- reinstall electrical wire harness cover
- reinstall all remaining parts

DO NOT START THE CAR HERE

- reconnect the battery
- Connect your OBDII Scanner and verify there are no codes in the system
- Perform Throttle Body Adaptation also known as a TBA Reset


Provided by louhas135 from e84.xbimmers.com

- Do Not Touch Break Pedal
- Put the “power o”n but do not start the engine. (insert key, press START button)
- Floor the throttle for 30-60 seconds
- Keep the throttle to the floor and put the power OFF (press STOP button)
- Release the throttle and wait 2 minutes.

During the 2 minutes you should feel or hear some kind of mechanical sound.

NOTE: At this time Throttle Body is fully reset and the SAV is ready to be driven (unless you drunk those two beers I told you about earlier)



SOME ADDITIONAL INFO

The Throttle Pedal looks way different compare to what you may have installed in your X5.
Here is a picture of what I used (again, you do not need to do this in this DIY)