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

[Arehman]

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

[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.

[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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[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

[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.

[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?

[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.

[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

[OldRanger]

Update: I don't think bench testing resistance (kOhms) is going to give reliable results.
Justification:

1. Even two, brand new sensors produce different values at 'full' counter-clockwise and 'full' clockwise.
2. The part of the sensor that rotates can wiggle or jostle in the sensor body, even at the stop positions and produce minor differences in the reading.

Stilt has provided the BMW tech manual description of how these work. That hasn't led me to a better testing approach. I suppose BMW Dealerships have sensor test equipment that can simulate throttle input to test the TPS sensors. The manual did help clarify the function of the pedal hall sensors. These are critical, because no one wants the lesser value.

Just as bigjae46 mentions...replacing them all would likely solve the problem, but there isn't a source for new pedals that I'm aware of. I have a spare used one, I suppose I can experiment with that one.

[bigjae46]

Update: I don't think bench testing resistance (kOhms) is going to give reliable results.
Justification:

1. Even two, brand new sensors produce different values at 'full' counter-clockwise and 'full' clockwise.
2. The part of the sensor that rotates can wiggle or jostle in the sensor body, even at the stop positions and produce minor differences in the reading.

Stilt has provided the BMW tech manual description of how these work. That hasn't led me to a better testing approach. I suppose BMW Dealerships have sensor test equipment that can simulate throttle input to test the TPS sensors. The manual did help clarify the function of the pedal hall sensors. These are critical, because no one wants the lesser value.

Just as bigjae46 mentions...replacing them all would likely solve the problem, but there isn't a source for new pedals that I'm aware of. I have a spare used one, I suppose I can experiment with that one.

I'd first try reflashing the ECU.

[OldRanger]

I'd first try reflashing the ECU.

OK, I did that (Epic Motorsports reflash). I also swapped the accelerator pedal with a used one I purchased back in May when I started having unexpected issues with two new TPS sensors. I chose to swap the pedal out because: 1) The most recent EML lights didn't put the car in limp mode. 2) The symptom I could feel, seemed like the car was bucking a bit when I would shift under heaving acceleration. Almost like it didn't know how much throttle to give. Given what the documentation says, I decided I would hedge my bets on a bad pedal.

My test drive included some WOT pulls and partial throttle shifting. No EML (knock on wood).

If I get another EML at the track I'm going to install the new throttle actuator and actuator arm that I have, and a new BMW TPS on the top/front position.

[ac427]

Update: I don't think bench testing resistance (kOhms) is going to give reliable results.
Justification:

1. Even two, brand new sensors produce different values at 'full' counter-clockwise and 'full' clockwise.
2. The part of the sensor that rotates can wiggle or jostle in the sensor body, even at the stop positions and produce minor differences in the reading.

Stilt has provided the BMW tech manual description of how these work. That hasn't led me to a better testing approach. I suppose BMW Dealerships have sensor test equipment that can simulate throttle input to test the TPS sensors. The manual did help clarify the function of the pedal hall sensors. These are critical, because no one wants the lesser value.

Just as bigjae46 mentions...replacing them all would likely solve the problem, but there isn't a source for new pedals that I'm aware of. I have a spare used one, I suppose I can experiment with that one.

Testing the TPS sensors on an analogue multimeter may help in seeing any deviation from a sweep of the wiper.

[Ryan_R]

If you want to try to nuclear overkill approach, there is always this option.

[OldRanger]

No EML today. Not at the track, nor on the way home.

[old///MFanatic]

OK, I did that (Epic Motorsports reflash). I also swapped the accelerator pedal with a used one I purchased back in May when I started having unexpected issues with two new TPS sensors. I chose to swap the pedal out because: 1) The most recent EML lights didn't put the car in limp mode. 2) The symptom I could feel, seemed like the car was bucking a bit when I would shift under heaving acceleration. Almost like it didn't know how much throttle to give. Given what the documentation says, I decided I would hedge my bets on a bad pedal.

My bad pedal absolutely put my car into limp mode. It also throws a code pointing to the pedal. You can just reset the pedal adaptations turning key On and holding pedal down. This can help with diagnosing and getting temporary out of limp mode.