Tps Starting At 2.44v On One Sensor. 0.6v On Other.

Would really appreciate some input.

My Ducati Multistrada 1200s 2010 has been jerking and cutting out, especially as I roll off the throttle. I suspected the TPS.

TPS secondary signal starts at 0.5V and climbs steadily to 4.8V (as it should) as I twist the throttle.

But TPS primary signal voltage starts at 2.44V ? and jumps around to 4.8V as I twist the throttle. How can that be such a high starting voltage? Short to voltage or a short to ground or bad earth somewhere?

I changed the throttle body (I have 4) and exactly the same situation.

Changed the ECU (2 spares) and no change.

Went through the manual and checked all the ECU pins and anything that is a ground and added an extra wire to ground them. = no change.

The primary and secondary TPS share the same power circuit and reads 4.99V.

Tried with the rapid bike EVO connected and disconnected. No change.

Tested APS and both primary and secondary sensors work fine and gives a clear pyramid signal on my Pico Auto scope as I open and close the throttle. TPS waveform is rather noisier (even with the lead properly grounded).

Checked the wiring harness both visually (by removing all the wrapping) as well as ohm testing the wires and grounds (disconnected from ECU). Some of the sensor earths don’t ground without the ECU plugged in.

I’m fresh out of ideas. Some more experienced input would be most welcome.

MTS1200s 2010 with Rapid bike EVO.

Would really appreciate some input.


My Ducati Multistrada 1200s 2010 has been jerking and cutting out, especially as I roll off the throttle. I suspected the TPS.


TPS secondary signal starts at 0.5V and climbs steadily to 4.8V (as it should) as I twist the throttle.


But TPS primary signal voltage starts at 2.44V ? and jumps around to 4.8V as I twist the throttle. How can that be such a high starting voltage? Short to voltage or a short to ground or bad earth somewhere?


I changed the throttle body (I have 4) and exactly the same situation.


Changed the ECU (2 spares) and no change.


Went through the manual and checked all the ECU pins and anything that is a ground and added an extra wire to ground them. = no change.


The primary and secondary TPS share the same power circuit and reads 4.99V.


Tried with the rapid bike EVO connected and disconnected. No change.


Tested APS and both primary and secondary sensors work fine and gives a clear pyramid signal on my Pico Auto scope as I open and close the throttle. TPS waveform is rather noisier (even with the lead properly grounded).


Checked the wiring harness both visually (by removing all the wrapping) as well as ohm testing the wires and grounds (disconnected from ECU). Some of the sensor earths don’t ground without the ECU plugged in.


I’m fresh out of ideas. Some more experienced input would be most welcome.


MTS1200s 2010 with Rapid bike EVO.





Sadly I can't help you, but I am with you because of a really similar situation with my APS (didn't check the TPS): the bike cuts when I pick up the gas just slightly, I suspect that the APS has some kind of misreading in a specific position. I have strange readings too, with a relevant difference between the main and the sub. I'd like to troubleshoot the problem too before buying a throttle body and replace the APS entirely.

2.44v seems correct. All the ECU needs to know is TPS voltage at fully closed. It doesn’t read from zero to 5v.

Correction Getting confused with degrees and voltage for TPS.

When I tuned an 1198S using an Innovate LM2 I had to input the voltages for the TPS throttle closed and throttle wide open. As the TPS was on the rear cylinder things were reversed. I found Throttle Closed was 4.71v and TWO was 0.86v. For a bike with the TPS on the horizontal cylinder these values would be reversed.

Your 2.44v would appear to be high then.

Just looked at the throttle body set up of your bike. The sensor on the front body appears to be the TPS. The one on the rear is the accelerator position sensor (appears motorised) [cruise control? What is activated using Tuneboy?]

I had a similar issue with a 1st gen Diavel which shares the early version of fly by wire throttle system with the 1st gen Multistrada. Eventually identified as a lazy throttle butterfly stepper motor which caused the mixed TPS and APS readings seen by the ECU which then went into melt down and cut the engine. Sadly none of the parts of the early throttle body assemblies are available as individual components although certainly the APS is removable. Andy

No it’s the other way around. The APS at the front of the bike sends a signal to the ecu and then the ecu tells the motor to activate the throttle bodies, which also houses the TPS.

That picture is upside down. The APS goes to the vertical cylinder and the TPS goes to the horizontal cylinder.

Alexaussi is right, the APS is on the front, right hand side. The TPS is on the left, on the rear cylinder

https://www.desmo-racing.com/en/tps-sensor-ipf5-multistrada-1200-diavel-1200-xml-426_425-5354.html

Appears to be non-linear.

So...what is being sold as a TPS is actually the Accelerator Position Sensor.

I cannot find the ‘TPS’ being sold separately. The same motorised Mikuni set up is used on the Mitsubishi Lancer and Outlander (Mikuni 57020).

Correct.

Anyway, here is a shot from my Picoscope.
Maybe the voltage is supposed to start at 2.5V on the sub sensor???... but I doubt it.

I’m not looking to replace the TPS as all 4 of mine show exactly the same symptoms... so highly unlikely it’s the TPS itself.

The voltage supply for both the TPS and APS come from the ECU. The APS gets two supplies from pin 43 (described as Sub) and 66 (described as Main) and 2 return signals at pin 50 (sub) and 66 (main). The TPS supply comes from 49 and it has two return signals at pin 57 (sub) and pin 68 (main). The ETV motor is connected to the ECU via pins 5,6,7,8,9. (The wiring diagram is in the back of the handbook for 2011 https://www.ducati.com/ww/en/service-maintenance/owner-manuals).

That’s great thanks.

Can someone please explain to me the electronic theory of determining the sensor signal voltage?

J'ai mesuré aussi les tensions sur les sorties TPS-Sub et TPS-Main. Les résultats sont bien différents entre les 2 capteurs.
Pour TPS-Main, la tension est linéaire en fonction de la rotation du papillon, de 0,6v (Papillon fermé) à 4,5v (Papillon ouvert) ce qui permet sans doute de connaitre la position du papillon par rapport à l'ordre moteur ETV.
Pour TPS-Sub, la tension varie brutalement de 3,4v à 4,4v autour de la position ralenti du papillon et ensuite monte très doucement à 4,5v ce qui permet de détecter à coup sûr la position 'moteur au ralenti'.

Google Translated
I also measured the voltages on the TPS-Sub and TPS-Main outputs. The results are very different between the 2 sensors.
For TPS-Main, the voltage is linear according to the rotation of the throttle, from 0.6v (Butterfly closed) to 4.5v (Butterfly open) which undoubtedly makes it possible to know the position of the butterfly in relation to the order. ETV engine.
For TPS-Sub, the voltage varies abruptly from 3.4v to 4.4v around the idle position of the throttle and then rises very slowly to 4.5v which allows the 'engine at idle' position to be detected with certainty.

I don't get it... The main one does make sense, but the sub doesn't (to me at least). What's the point in such a strange behavior? I would understand if the sub would go from 4.x to 0.x (reversing the main one, as a mirror) to check, but not like that... What am I missing?

Je pense que le capteur TPS-Sub permet seulement de détecter la position moteur au ralenti mais de façon beaucoup plus précise qu'avec le capteur TPS-Main. S'ils avaient le même fonctionnement linéaire, ils seraient installés au même endroit ou à l'opposé. On voit que la position des 2 capteurs est différente par rapport au secteur aimanté pour augmenter ou diminuer l'effet Hall en fonction de la position du papillon de façon différente. L'électronique doit aussi être différente pour avoir un comportement linéaire pour le capteur TPS-Main et un comportement exponentiel pour le capteur TPS-Sub.

If you want more accurate translations from French to English or the other way around, use DeepL translator (deepl.com)
Google translate throws up some weird stuff.

Thanks for the reply Francois, I understand the logic behind it, but the fact that I can't really grasp how it actually works is probably (surely) a lack of knowledge of mine... Never really dived into the electronics enough. But again, thank you, I never saw the TPS internals anyway.

This thread continues at https://www.ducatiforum.co.uk/threads/tps-starting-at-2-44v-on-one-sensor-0-6v-on-other.79170/ .

needs a thread merge.. @El Toro