SOLVED-Trifecta after drivetrain work???

[Ricky Bobby]

I would also take Brandon002's advice and use OBC test 7 for voltage while running, just to rule out a bad alternator.

However if the odometer works and cruise works, you're almost certain its one of the sensors. You could always buy one and guess on which side it is, if it doesnt work on the first side then put the new sensor in the other side and swap the other one over, should be working by then LOL!

[ChevDog1]

Originally Posted by Ricky Bobby

I would also take Brandon002's advice and use OBC test 7 for voltage while running, just to rule out a bad alternator.

However if the odometer works and cruise works, you're almost certain its one of the sensors. You could always buy one and guess on which side it is, if it doesnt work on the first side then put the new sensor in the other side and swap the other one over, should be working by then LOL!

I hope the alternator is not bad - just did that about a year ago.

I could be making the payments on a new car for what i have put into parts in this POS over the last year...

[bcredliner]

Originally Posted by ChevDog1

The above link indicates that the right rear wheel sensor controls the speedo, but everything else I have read says that if the speedo is out, its the left sensor - which is correct?

My guess is that if 2010 Bavauto blog is wrong they would have corrected the error by now.

[ChevDog1]

OK - just drove it to get a sandwich.

Speedo - not working
Trifecta lights - all on.
odometer - not moving
trip meter - not moving
MPG meter - not working
Tach - working normally
Cruise control - working normally
hill descent control - not working

All other parts of the car appear to be functioning normally.

[bcredliner]

BMWs are very sensitive to out of spec voltage. A bad battery or alternator can cause what you are experiencing. If battery is old suggest you have it load tested. Many auto parts stores with do that at NC. Suggest you monitor the alternator while driving as suggested.

[ChevDog1]

i will watch the voltage on the way home tonight. What should i be looking for?

[Ricky Bobby]

look for going under 13 or over 14 while running, it should stay in 13.1 - 13.9 range or so I believe.

If the cruise works its almost definitely a rear sensor though.

[ChevDog1]

Originally Posted by Ricky Bobby

look for going under 13 or over 14 while running, it should stay in 13.1 - 13.9 range or so I believe.

If the cruise works its almost definitely a rear sensor though.

Probably LEFT rear?

[upallnight]

Originally Posted by ChevDog1

Probably LEFT rear?

Yep!!!

What I posted in my first post.

If you can't find someone with BMW specific software to scan the X I would recommend that you go and buy the cable and BMW Scanner 1.4 so that you will have it around to do future diagnostic. BMW Scanner 1.4 is the easiest of all the software available to setup on a laptop or computer running windows XP.

[ChevDog1]

Thanks!

I just ordered one from my local NAPA, and will pick it up on my way home tonight. I'll post back after I have installed it.