Making the throttle reliable...and how quickly can you kill a TPS?

[Stilt]

I'm sure someone with better EE / ECU knowledge will chime in, but my interpretation of the measurements was that the ECU is looking for the two TPS sensors to agree with each other and line up with the pedal input as the engine responds. When my sensors failed, the EML + limp mode was guaranteed to kick in after a full / high throttle application, which I'm guessing was the case because the deviation grows linearly and exceeds the acceptable tolerance at the end of the range. Also want to note that I updated my original table as the calculation of range was adding the high value to the low one, and subtracting them is probably the right number to compare, if this analysis holds any water at all 😂

There does exist another failure mode on these TPS sensors, where you'll see the resistance zero out at some point while sweeping through the range. My understanding is this is caused by some corrosion of the contacts inside.

I'd be curious to know if the VNE's FCP discontinued were actually OE on our cars, or if they were indeed Hella or some other manufacturer as Altaran suggested despite VNE units clearly having logos ground off. Having gone through so many VNE units myself, it wouldn't surprise me if FCP dropped it from their catalog because of high warranty replacement rates, in which case maybe OE is the best guarantee of reliability on this one.

https://drive.google.com/file/d/1C4VmUVGRwu54eh-nuhFQdXwNxDBF_WCz/view

[dukeofchen]

Thanks for including those resistance test results. I'm not knowledgeable in the realm of multi-meter testing, but I do have one - so I'll give it a try.



Note on test results: The used TPS is the top one, I just pulled it off my car for this test. I'm not suggesting it's the cause of the EML, it's just the easiest one to get to. On this occasion the EML error was not accompanied by a limp mode. The sensor is a VNE, it's a few months old including 7 track days some with very high ambient temperature (over 100F) moderate oil temp and high coolant temperatures.

P.S.: A resistance test is certainly easier than creating a 5V power source and testing voltage to compare to spec. Would someone with more knowledge on this help me understand if the resistance test is valid for determining if a sensor is bad?

I'm sure someone with better EE / ECU knowledge will chime in, but my interpretation of the measurements was that the ECU is looking for the two TPS sensors to agree with each other and line up with the pedal input as the engine responds. When my sensors failed, the EML + limp mode was guaranteed to kick in after a full / high throttle application, which I'm guessing was the case because the deviation grows linearly and exceeds the acceptable tolerance at the end of the range. Also want to note that I updated my original table as the calculation of range was adding the high value to the low one, and subtracting them is probably the right number to compare, if this analysis holds any water at all 😂

There does exist another failure mode on these TPS sensors, where you'll see the resistance zero out at some point while sweeping through the range. My understanding is this is caused by some corrosion of the contacts inside.

I'd be curious to know if the VNE's FCP discontinued were actually OE on our cars, or if they were indeed Hella or some other manufacturer as Altaran suggested despite VNE units clearly having logos ground off. Having gone through so many VNE units myself, it wouldn't surprise me if FCP dropped it from their catalog because of high warranty replacement rates, in which case maybe OE is the best guarantee of reliability on this one.

[OldRanger]

Took some multimeter measurements last time I had one go kaput. Can see how the resistance ranges have drifted on the failed ones, which I'm guessing would be a linear-ish process as the sensors age.

Thanks for including those resistance test results. I'm not knowledgeable in the realm of multi-meter testing, but I do have one - so I'll give it a try.



Note on test results: The used TPS is the top one, I just pulled it off my car for this test. I'm not suggesting it's the cause of the EML, it's just the easiest one to get to. On this occasion the EML error was not accompanied by a limp mode. The sensor is a VNE, it's a few months old including 7 track days some with very high ambient temperature (over 100F) moderate oil temp and high coolant temperatures.

P.S.: A resistance test is certainly easier than creating a 5V power source and testing voltage to compare to spec. Would someone with more knowledge on this help me understand if the resistance test is valid for determining if a sensor is bad?

[bigjae46]

Another track event, another EML on the way home (Driving from West Virginia Hillfest at Snowshoe Mountain; code occurred about 1 hour after leaving venue after some miles of partial throttle behind slow traffic). Codes 76 and 78 again.

Today, I noticed that FCP Euro does not sell the VNE aftermarket BMW Throttle Position Sensor, VNE-4166000 any longer.

I ordered a Genuine BMW part so I can try the heinzboehmer approach. It would be nice to have the tools to bench test these sensors, so I could be smarter about solving the problem.

I'd replace the 2 TPS and gas pedal at the same time. Clear adaptations and reflash any aftermarket tune.

I'd imagine you can bench test the sensors by checking resistance.

[dukeofchen]

Have gone through a couple VNE's over the years at the top position, while the OE sensor in the lower position is still kicking (I'm guessing it's original).

Took some multimeter measurements last time I had one go kaput. Can see how the resistance ranges have drifted on the failed ones, which I'm guessing would be a linear-ish process as the sensors age.

I wonder if the top one is just more prone to failure since it's exposed to way more heat than the lower one?

Edit: realized the range calc in my original table was wrong

[Altaran]

As far as I know Hella is the T1 supplier for these parts.
I have replaced the front unit twice with aftermarket and failed within 5k kilometers. Last time I used Hella and no issue since 30k kilometers.

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[old///MFanatic]

The aftermarket ones are only good for 10k miles max. Go genuine bmw on the TPs sensors.

VNE are the exact ones that BMW sells. I have over 50k on mine. But since these are NLA I agree to go Genuine BMW now.

[Arehman]

The aftermarket ones are only good for 10k miles max. Go genuine bmw on the TPs sensors.

[Stilt]

Another track event, another EML on the way home (Driving from West Virginia Hillfest at Snowshoe Mountain; code occurred about 1 hour after leaving venue after some miles of partial throttle behind slow traffic). Codes 76 and 78 again.

Today, I noticed that FCP Euro does not sell the VNE aftermarket BMW Throttle Position Sensor, VNE-4166000 any longer.

I ordered a Genuine BMW part so I can try the heinzboehmer approach. It would be nice to have the tools to bench test these sensors, so I could be smarter about solving the problem.

You should be able to test the sensors with just a multimeter. If you rotate the sensors and have the multimeter's leads touching the sensor, you can see if the sensor outputs the correct volts. You could get fancier and get a female connector for the sensors. Then, solder wires to the pins of the female connector (so you are essentially making a bench testing harness), then use gator clips so you don't have to hold the multimeter leads on the sensor directly.

https://drive.google.com/file/d/1C4VmUVGRwu54eh-nuhFQdXwNxDBF_WCz/view?usp=sharing

[heinzboehmer]

It would be nice to have the tools to bench test these sensors, so I could be smarter about solving the problem.

They're basically just a potentiometer, so a regular multimeter would work to bench test them.

However, the hard part would be getting the ambient conditions correct so you can replicate the failure mode. I've had success putting parts in the oven when trying to reproduce a thermal related electrical failure, but it's far from an exact science.

[OldRanger]

Another track event, another EML on the way home (Driving from West Virginia Hillfest at Snowshoe Mountain; code occurred about 1 hour after leaving venue after some miles of partial throttle behind slow traffic). Codes 76 and 78 again.

Today, I noticed that FCP Euro does not sell the VNE aftermarket BMW Throttle Position Sensor, VNE-4166000 any longer.

I ordered a Genuine BMW part so I can try the heinzboehmer approach. It would be nice to have the tools to bench test these sensors, so I could be smarter about solving the problem.

[old///MFanatic]

What am I doing wrong if none of these sensors have failed on me in over 100k miles? lol

My front sensor failed around 160k and rear around 185k. Pedal failed around 205k.
TPS sensors were replaced with VNE, no issues in years. Pedal was replaced with new current BMW.

Linkage fine and never replaced.

[OldRanger]

I replaced all 3 at the same time and then cleared the adaptations.

Good thinking. Did you have a new pedal, or used?

[bigjae46]

I replaced all 3 at the same time and then cleared the adaptations.

[PetrolM3]

Perhaps they were replaced before my ownership- but I live in TX and it is exceptionally hot here, and I flog the car on a daily basis.

Then either you are very lucky or they were replaced in the past. I recently sold my M3 with just over 100K miles with all 3 units replaced. The new owner is a collector and has many cars, so he may not drive it enough to experience any failures and may also some day wonder how he's so lucky that he hasn't experienced any failures.. lol