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Discussion Starter #1
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.
 

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V=I*R

Just shooting from the hip on this one...my throttle went kaput on my m821...wires to the unit were fouled pretty bad...it was sending garbage signals through all the oxide to the ecu...never did any ohms reading on the unit itself but going by your findings...of 2.44v...the increase is due to added resistance...my gut says a shite wire...you would never notice anything wrong until you peel back some of the wires coating...but in any case...that's why your voltage is spiking...now to find the path of most resistance

 

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Discussion Starter #3
That makes sense, so I Ohm tested the wires concerned and they have low resistance of about 0.5 ohms.
 

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Testing a fouled wire like that is tricky...because you naturally scrub the surface for better contact...the wire in the picture was brought to the point of failure over the course of 36k miles...a miserable last 18k for sure...I think you might have some luck using jumper wires to help in diagnosing...nothing is terribly fun tracking down electrical issues...but swapping out parts goes a long way to isolating it
 

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Discussion Starter #5
Ok. Will retest the wires and add jumper wires. But do you know if:

1) it is possible the sub sensor signal SHOULD start at 2.5V?

2) There should be no ground on several of the “earth” wires that come out of the ECU when ignition is switched off?
 

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Ok. Will retest the wires and add jumper wires. But do you know if:

1) it is possible the sub sensor signal SHOULD start at 2.5V?

2) There should be no ground on several of the “earth” wires that come out of the ECU when ignition is switched off?
Hopefully someone more familiar with your model can answer those...but I'm fairly sure starting voltage should be near 0
 
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