Thottle Position Sensor Adjustment
Have ignition key in 2nd position. As the wires go, on the engine side we have a Brown, Black and Yellow wire. On the TPS side we have a Black,Green, and Orange wire. First don't measure between Black and ground. Measure between orange & Black on TPS side or Black and Brown on the eng. side. Look closely and you will see the black wire does not stay the black wire through the connection. eng. side black (is a ref. ground not the same as battery ground turns to orange, the brown 5v pull up resistor circuit wire turns into black on the TPS side. So on one side black is 5v and on the other side its ref. ground. (just don't know how it happened) Anyway the yellow wire (near resistor) turns to green. At full throttle on the TPS side, Black is 5v, orange is (ref ground) and green is at it's peek 4.78v. with a voltage test from green (-) at. 4.78v and Black 5v ref. your tester should read the difference at .22v. This is the updated procedure from BMW in form of a service bulletin. You have to use a digital voltmeter never analog. (Analog will short the two together because of no impedance. use at least a 20 Mega Ohm meter.
Try it this way, loosen both screws on resistor, move it so you are sure the throttle butterfly is closed, now measure on the Engine side (leave plug plugged in) between black and brown, lets assume you get 4.75volt, then your next goal will be -.22 from that which eq, 4.53, now put leads between brown and yellow, hold at full throttle and fine tune so you get the 4.53volts, when done make sure you hear the click as well.