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About the resistive hack:

I would try a 3.3kohms (orange orange red) between the 5v and the center pin, and a 12kohms (brown red orange) between the center pin and ground pin. If this works, it will go in my toolkit with the spare fuses, right now!

(if it works, any 1:4 relation between resistors would probably work in the vicinity, like
1.2 kohms + 4.7 kohms,
or 1.5 kohms + 5.6 kohms,
or 3.9 kohms + 15 kohms,
or 4.7 kohms + 18 kohms.
(I'm giving standardized 10% resistor values).

But like I wrote, I suspect the manual tells to test for ~4 volts but wouldn't bother explain why it's 4V on a DC multimeter, when it could easily be a square wave of 5V with a 80% duty cycle....

So, measuring with the AC voltmeter might show something interesting without requiring an oscilloscope. If you pick up any AC voltage when upright, the resistor hack likely won't work.
 

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Guys, I was too curious, so I went testing. Here are some results:

test1: replace vehicle down sensor by 3.3 kOhms + 12 kOhms hack
bike starts and doesn't stop. While bike is idling, I yank out the resistors: bike doesn't stop!

test2: unplugged the vehicle down sensor (VDS)
bike starts just fine and doesn't stop.

WTF?
I suspect this is because I was in neutral? Well, if I recall the long post, the bike should shut down even in neutral...
My bike is gen3 (2015).
I turn off ignition between every test.
My hypothesis is that upon ignition, if the VDS is not present, it is ignored? Then that's an easy fix on the road! (Just disconnect and move on)
 

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I think your test is flawed, also explain what the 3.3 and 12K resistors were connected to, I assume the 12 K was BL to Y/G and the 3.3 was Y/G to BR/BK
I did explain in post 24. If you want 4V out of 5V, the higher resistor need to be on the ground side. So exactly the opposite of what you wrote. 3.3kohms should be on the +5v (blue) side and center (yellow). To the casual reader, if you don't know what a tension divider is, stay away from electronics and the hacks discussed here. LOL!


Keep in mind there is a scan time allowed ( 3 to 5 seconds), also in testing bypassed does a error code get sent and display on the gauges? Will it run indefinitely in the bypassed mode?
Yeah, I gave it a fair 5+ seconds. Every test. With ignition off-on every test. I have not looked for "error codes" of any kind. Bike just ran fine (in neutral) in all cases. I suspect the ECU expects low vs high voltage (binary) and it may have a pull up resistor, so when disconnected, it shows as high voltage, thus thinks the bike is "upright". It makes sense that engineers would design to tolerate circuit failures like a broken cable or connector.

I intend to remove the dash upper cowling and go ride with the VDS disconnected, reconnecting if it fails/ Maybe tomorrow. Someone else can report results too (scientific method).
 

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I did explain in post 24. If you want 4V out of 5V, the higher resistor need to be on the ground side. So exactly the opposite of what you wrote. 3.3kohms should be on the +5v (blue) side and center (yellow). To the casual reader, if you don't know what a tension divider is, stay away from electronics and the hacks discussed here. LOL!




Yeah, I gave it a fair 5+ seconds. Every test. With ignition off-on every test. I have not looked for "error codes" of any kind. Bike just ran fine (in neutral) in all cases. I suspect the ECU expects low vs high voltage (binary) and it may have a pull up resistor, so when disconnected, it shows as high voltage, thus thinks the bike is "upright". It makes sense that engineers would design to tolerate circuit failures like a broken cable or connector.

I intend to remove the dash upper cowling and go ride with the VDS disconnected, reconnecting if it fails/ Maybe tomorrow. Someone else can report results too (scientific method).
See post 26 , As I think I stuck my foot in my mouth here. Yes I make mistakes too :eek::rolleyes:

Voltage is equal to current times resistance. Supply positive is BL ( @5VDC) supply negative is BR/BK . Output is Y/G Total circuit R is 12K +3K = 15 K . Current is volts divided by resistance 5 VDC /15k = 0.00033 amps

Volts across 12 k resistor is 0.00033 X 12k = 3.96 VDC.
[/B]

To go one step further you could measure the current through the Y/G wire to the ECU. Take that current and calculate the resistance required to produce a 1 volt drop , say it was 1.3 milliamp current ( R= E over I) = ( 1VDC divided by 0.0013 amp) = a 769 ohm resistor @ 1/4 watt or less. Therefore you would only need one resistor. Big difference between a voltage divider and something to produce a series voltage drop on a fixed load.
 

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Voltage is equal to current times resistance. Supply positive is BL ( @5VDC) supply negative is BR/BK . Output is Y/G Total circuit R is 12K +3K = 15 K . Current is volts divided by resistance 5 VDC /15k = 0.00033 amps

Volts across 12 k resistor is 0.00033 X 12k = 3.96 VDC. You do the math, and it is called a voltage divider, when you correct me make sure I have made a mistake first.
Hi onewizard, I don't know how the discussion turned this way but I feel some anger coming my way. I trying to help. I have an electrical engineering degree so I think I thought I could actually help. I can move along if you really prefer so.

This below is what I tried. I simply pointed out that you indicated to put the 12kohms on the blue side which is wrong. I also assume the ECU input (yellow) is high impedance and doesn't draw any significant current but merely detects voltage, as any modern microcontroller input would. I tried to respect the hinted approximate 16kohms in other posts as a starting point.

Anyway. Here is my diagram. I'll shut up now.

 

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Colour coded and Accurate

Hi onewizard, I don't know how the discussion turned this way but I feel some anger coming my way. I trying to help. I have an electrical engineering degree so I think I thought I could actually help. I can move along if you really prefer so.

This below is what I tried. I simply pointed out that you indicated to put the 12kohms on the blue side which is wrong. I also assume the ECU input (yellow) is high impedance and doesn't draw any significant current but merely detects voltage, as any modern microcontroller input would. I tried to respect the hinted approximate 16kohms in other posts as a starting point.

Anyway. Here is my diagram. I'll shut up now.

Well when I screw up , I do a good job of it, eventually I will edit out my mistakes in the previous post. Many times when I had problems on complex circuits I would draw it out, this time I figured I was smart enough and my memory was good enough that I could do it in my head. So in the drawing, measuring across
the 12 K resistor will give approx. 4 VDC, the key is that the input to the ECU must be positive with respect to ground, therefore one side of that 12K resistor must be connected to ground.

So I was 100% wrong :sorry:

Also :thanx: for taking the trouble to provide a accurate drawing.
 

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You are welcomed!
I love this forum, so much nicer people than some other forums I won't name.

But I have to restate my disclaimer: the vehicle down sensor (VDS) may be an active device with a protocol with the ecu; the fact that my hack "may" work no better/no worse than disconnecting the VDS, is a point in favor of that...sadly. I'm eager to test that tomorrow, hopefully.
 

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I am pleased to announce that I was both right and wrong about the vehicle down sensor (VDS for short).

a) disconnecting the VDS is not a workaround. The checking time from the ecu is longer than 5 seconds. I suspect it is on some internal clock so it can be quick or slow. Feels more like 8 seconds.

b) the resistive hack WORKS! I rode 5 minutes. No issue, no odd lights. ECU completely fooled. And if I disconnect it wile running, bike turns off within the usual 8sec.

This is before putting duct tape to hold in place. Something more tightly fitting would be recommended, as it is rather unreliable like this, and not waterproof.

 

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Single Series resistor / Voltage Drop

I am pleased to announce that I was both right and wrong about the vehicle down sensor (VDS for short).

a) disconnecting the VDS is not a workaround. The checking time from the ecu is longer than 5 seconds. I suspect it is on some internal clock so it can be quick or slow. Feels more like 8 seconds.

b) the resistive hack WORKS! I rode 5 minutes. No issue, no odd lights. ECU completely fooled. And if I disconnect it wile running, bike turns off within the usual 8sec.

This is before putting duct tape to hold in place. Something more tightly fitting would be recommended, as it is rather unreliable like this, and not waterproof.

What I found is the ECU current from the output of the VDS is 36.45 micro amp as measured using a Fluke 189, on my 2015. Input voltage is 5.01 VDC as measured using a Fluke 189.

Voltage at the output of the VDS 3.98 to 3.99 VDC at idle running, with battery @ 14.2 to 14.3 VDC . I used a 32.6 K ohm resistor in series with the Blue and Yellow Green which gave a VDC 3.89 VDC ( voltage drop of 1.11 VDC) . I also used a 38.9 K ohm which produced a 3.73 VDC output ( voltage drop of 1.27 VDC). Both cases the bike ran for 5 minutes, when the wire fell out, it shut down around 7 seconds.

So both resistors are readily available. I have created a voltage drop equal to what the sensor input is,by measuring the current and by what I calculated ( original called for a 30,660 ohm resistor. The ones I used I had plenty in stock.

So if I would be a person heading out on a long trip with a MK-1 and you had similar trouble but it went away ( yes I would buy a new sensor however) as a backup you could first try either the 32.6K or the 38.3 K resistor, fold the ends over to double the thickness and insert between the Blue and Yellow
/ Green , measure VDC to ground from the yellow / green side of the resistor,if you are in the ball park of the values in the manual or those I displayed, pack a roll of electrical tape and I would suggest taping the resistor to the wiring harness of the VDS , give the tape a double rotation before ripping off, this is your start to remove the tape (the 2015 there is a frame ground less than 5 inches from the sensor)

36.55 micro amp DC Notice to the left of the 36.55 there is no triangle like the last photo, that is because one lead fell out and I keyed off, and noticed a error of 0.09 micro amps possibly induced, so the last photo I used REL to zero the display. ( ya I know, all gobbledygook :nerd: just remember, eventually some of this may sink in >:) well if you read it enough) :huh: ;) Also note the photos from dddd are much clearer and easier to understand. And that is the difference between a Master Electrician with Electronics and a Engineer >:)


I am measuring between the left Blue 5.01 VDC supply in series with my Fluke meter on micro amps DC and the center input Yellow /Green

Using REL as there was a error of .09 micro amps with the leads disconnected, probably induced, but you will see a triangle to the left which indicates REL ( very similar to zeroing the resistance of the leads when measuring resistance)

Output of VDS @3.98 VDC




Using a single 32.6 K resistor between the Blue and Yellow 3.89 VDC


Using a 38.9 K resistor @ 3.72 VDC


Actual micro amps after using relative, really didn't need to but the meter read 0.09 micro amps high with open leads.



Here is the active thread where further questions and discussions can take place. From time to time updates get copied to this thread, intent is to keep all discussions in the technical discussion thread, as posting count restrictions limit this thread to long time members.


https://www.kawasakiversys.com/foru...itch-bike-fell-down-vehicle-sensor-issue.html

And a second related one:

https://www.kawasakiversys.com/foru...66-vehicle-down-sensor-engine-not-firing.html
 
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I am pleased to announce that I was both right and wrong about the vehicle down sensor (VDS for short).

a) disconnecting the VDS is not a workaround. The checking time from the ecu is longer than 5 seconds. I suspect it is on some internal clock so it can be quick or slow. Feels more like 8 seconds.

b) the resistive hack WORKS! I rode 5 minutes. No issue, no odd lights. ECU completely fooled. And if I disconnect it wile running, bike turns off within the usual 8sec.

This is before putting duct tape to hold in place. Something more tightly fitting would be recommended, as it is rather unreliable like this, and not waterproof.

There are days when I am truly grateful for having members like this, taking the time and effort to share their knowledge-we all learn by it-I can be grumpy at times, but I recognize intelligence also-Thanks again @dddd --A extremely valuable member!
 

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