DIY: BMW Throttle Position Sensor Testing

Video tutorial on how to test/troubleshoot and setup the throttle position sensor on a BMW. A faulty throttle position sensor in known to cause poor fuel economy, loss of power, erratic idling, high idle, and increased emissions. This does apply to the older model/style throttle position sensors, the newer models use a potentiometer. If you are removing the sensor, I would also recommend changing the two phillips screws as well because they can be easier to strip as compared to a hex head bolt or allen head bolt. This particular tutorial was done on a 1984 BMW 733i equipped with an M30.

Tools/Supplies Needed:
-multimeter
-phillips screwdriver
-razor knife
-standard/flat screwdriver

Procedure:
-first step is the ensure the throttle position sensor is step up correctly
-with the throttle plate fully closed, open the throttle very slightly and you should be able to hear an audible "click"
-if not the sensor is either broken or not adjusted correctly
-with the throttle plate fully closed, loosen the two phillips screws and rotate the sensor all the way clockwise until you feel it stop
-do not go too far so it opens up the throttle plate
-tighten down the screws
-now retest to see if it has an audible "click", if not the switch is broken
-now testing with the multimeter, remove the wiring harness plug
-on the side of the throttle position sensor, there will be numbers
-3 (wide open throttle), 18 (input single), 2 (idle)
-using the multimeter on the ohms setting, we will be testing each plug to ensure it is working correctly
-with the throttle close, there should be continuity between pinouts 2 and 18, and an open circuit between pinouts 3 and 18
-with the throttle increased slightly, there should be an open circuit between pinouts 2 and 18, and an open circuit between pinouts 3 and 18
-with the throttle fully opened, there should be an open circuit between pinouts 2 and 18, and continuity between pinouts 3 and 18
-if the test fails, the sensor does need to be replaced
-the sensor can be opened up, although it is somewhat difficult
-using a razor knife, cut around the seam to break the glue
-then using a small standard screwdriver, slowly pry away the case
-once open, you can spray the microswitch with contact cleaner or clean the wide open throttle contacts (this is a temporary fix, I would recommend buying a new replacement sensor)

Thank you to all those who watch my videos and support my content. Don't forget to subscribe to my channel for future tutorial videos and like my video if you found it helpful. New videos are always being uploaded every week!

© 4DIYers 2013
All Rights Reserved
No part of this video or any of its contents may be reproduced, copied, modified or adapted, without the prior written consent of the author.

[ClassicBMWFanInQuebec]

This video is excellent. It confirmed that the WOT contact is silent and not an audible click. I thought my TPS unit was bad because I knew it had two stages (idle and WOT) but I could only hear one click. Thank you sir!

[jandeman]

Worked great on my E34 535i now running much better at idle. Before it was stuck at 1000rpm

[YarraMates]

just sorted out high idle on my 635. Very helpful, thank you!

[sergio.baggedE]

Great video, I had a idle and low rev problems with my bmw m20 engine, change everything, maf, icv, harness... and saw this video. problem was in tps it was full of oil. after I clean it and adjusted it, engine works perfect.
Thanks

[BMWacuraFTW]

BMW E30 (M20 engine) has the same throttle position sensor located under the throttle body instead of the side. Fixed my high idle issue when warm (idled to about 1800-2500 RPM when warm). If you let the car warm up without touching the accelerator and it idles fine, but starts to idle high when you start driving around, you know its likely to be your throttle position sensor not telling the ECU its supposed to be idling the engine. Hence the high revs :P

[mrjaybennett]

Thank you so very much for this beautifully done, well articulated, informative tutorial.

[pokerdotjearsy]

Thank you so much for this video! Saved the day on my e30 m20b20 - was able to test before pulling apart (tps is hidden under throttle body)!

[Resq]

Hello, thanks for posting. I have a “dead spot” in my throttle, when I press down on my accelerator pad pedal the first quarter to half inch movement I get a pause and then continue to accelerate. Is this a sign of a faulty, throttle positioning sensor as well? Thank you.

[SnowboardShredz]

Might sound stupid but with the throttle body at idle do you want the micro switch to be engaged at idle or engage after giving the slightest amount of throttle?

[PandaBewok]

When wide open throttle, how about pin 1 and 2? Open circuit or close circuit?

[CATPLAYING]

My bmw e39 rpms go up and down only when driving not on idle, could the TPS be related to this? I also think there is a small lack of power too but I basically bought the car with this problem.

[sembongers]

Hey man, I have an 320i e30 myself. When I start it up it idles at around 2k, when it's al warmed up it drops down to about 1k. Do you think the high idle could have anything to do with this sensor?

[giicllc]

Great video!, Now i am wondering if you can help me figure out how to fix my 2002, 318i n46 right hand drive with 45k miles on it, which i imported from Japan. I am an American Living in the Kingdom of Tonga (tiny island nation in the South Pacific with NO BMW MECHANICS, only Bush mechanics). I am on a fast learning curve. Car suddenly developed a very rough Idle, and major studder upon acceleration. Runs terrible, sounds terrible.Now i checked for vacuum leaks visually and with carb cleaner, nada. Cant get parts here but managed to find new spark plugs which cost me over 150usd and Changed them out (NGK Laser Platinum). Still same issue. Put injection cleaner and filled up gas tank, only ran that for about 10 miles (not to far to go around here) still same worse seems. Got a hold of a decent scanner and got the following error codes: 27E?, 2743 (miss fire in cylinder 3), 2785 Throttle Potention Meter, 2786 Throttle Valve potention meter 1 & 2787 Throttle Valve Potention meter 2. Now where is this part located on the n46 engines, 318i, and what can i do to even temporarily fix until i can order a replacement which will take 8 to 10 weeks to arrive.
I am all Ears and Thanks a bunch in advance!

[Gioagla]

Hello
Please tell me where is connected the front hall sensor from the crankshaft
I have the 3 wires cinnected to the diagnose plug, and i m sure someone did some bullshit here, also i cannot find other free wires of the harness around the plug
Mutch aporeciated if you help
Cheers

[thomasposeyunknownhero]

If my sensor doesn’t have resistance at WOT is it broken? Car is having rough idle and shaking. 800 rpm

[gentlemandriven]

I believe Im having an Issue with my TPS as well but that my car is not realizing it is no longer at idle.

[j.collett]

Would this cause the engine to idle at 3k? The M30B35 in my 91' 535i idles that high and if you touch the throttle almost runs away like a diesel. I had to shut it down as it neared 5k and showed no sign of slowing down.

[sbadly]

Holly crap I might just have found my problem!! 2011 x3 3.5 xdrive

[asuhdude]

Hi I'm about to buy a 1999 bmw 323i but has a "bad" body throttle sensor I found another 323i and am taking that body throttle any advice at what I should do should I take it to a mechanic? What would be a fair price to pay just to swap it? Should I do it myself? Any advice will be appreciated -thanks cx

[gonsaporiti]

Great explanation. Thanks for sharing!