The signal you are reading is what is called a processed value. It will NOT give you a lab scope line wave/steps.

In order to get a true value of TPS readings you will need a lab scope. But there is an alternative. Just read it with the engine off but key on through the OBDC port with a scanner. It will put you in the ball park to see if it functions. When they fail the volt values jump all over so there usually no codes being set, just input the engine management systems can not comprehend so it does stupid stuff. Most shops choose the "when in doubt replace" methodology as it is after all 15 years old and only has a 100 thousand mile cycle life.....

If you purchase the BMW laptop software you can see the values live and any captured failures
Helpful?

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2005 X5 4.8IS
The Blue ones are always FASTER....

Current Garage:
2005 X5 4.8is
2002 M5 TiSilver
2003 525iT
1998 528i
Former Garage Stable Highlights
2004 325XiT Sport
1973 De Tomaso Pantera, L Model
1970 Dodge Challenger T/A 4 sp Alpine White
1970 Dodge Challenger T/A 4 sp GoManGo Green
1971 Dart Sport, “Dart Light” package
1969 Road Runner 383
1968 Ply Barracuda 340S FB Sea-foam Green