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Discussion Starter #1
Hi guys :smile:

It seems that the bike which I purchased with a salvage title never had it's speedometer fixed. It displays 0 nonstop. I have decided to return the beast into its formal glory :thumbsup:

Having limited tools I was able to measure some voltages.

- Input voltage by ECU ~ 4.9 V
- Input valtage by sensor ~ 2.5 V
- I also measured by this place (look pic) - left and middle wires ~ -1.14 V :dontknow:

The wires look everywhere stock. No one has tempered with them. The manual points to the wiring, but could it be the actual speed sensor? Should I go over the wiring? Look for anything specific?

The bike throws out fault codes 24 and 25.

Thanks :smile:
 

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Discussion Starter #2
...
- I also measured by this place (look pic) - left and middle wires ~ -1.14 V :dontknow:
...
After taking a closer look at the diagram in the service manual, I believe that what I measured this way was the output voltage however without moving the wheel.

Those values seem way out of spec. I will check them again tmw and see if I can get down to the problem.

Anyone have any experience with this?

Thanks.
 

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Discussion Starter #3
I have finally replaced the speed sensor and the issue is still there :dontknow: :sad:

After getting a newer service manual I was able to get proper voltage measurements for each section.

- Input voltage by ECU - 4.9V
- Input voltage by sensor - 1.3V
- Output voltage by sensor - 4.9V - static, doesn't change when wheel is rotated

How is it possible for a sensor to receive only 1.3V and output 4.9V? I'm cluless to what can be wrong? Is the low input voltage causing it to output a static high voltage or is it getting the extra power from a different place?

Thanks.
 

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Discussion Starter #4
Quick question guys.

Does the ECU provide any voltage on the BL/Y cable which provides the output voltage from the speed sensor? So if I unplug the sensor, the BL/Y cable should have 0V?

Thanks
 

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First, the circuit. The ECU provides the 5Vdc to the sensor to power it and provide a reference voltage for it to work. Looking at the diagram, the 5Vdc is supplied on the BL wire. You should be able to disconnect the sensor and measure ~5Vdc on the BL wire to chassis ground to verify the proper input voltage. If you're not getting that, something's wrong. Obviously. :lol:

The other 2 wires coming out of the sensor are the ground (BK/Y) and the sensor signal itself (BL/Y). The ground line goes through a joint connector which may be the issue providing a poor or inconsistent ground. The signal line is split to go back to the ECU but also the instrument cluster.

So, a couple of things to check. Since I read you already replaced the sensor, it's safe to assume that it's probably OK. But, I'd re-verify the input voltage to it (~5Vdc) and then check the output voltage by spinning the wheel. This is going to be tricky because I'd run stand-alone jumper wires to the sensor to be sure it's not a harness problem. With the connector off the sensor, jump the 5Vdc line to the sensor, then jump the ground line from the sensor directly to the chassis, spin the wheel and measure the output signal between the output and the chassis ground. This would isolate the sensor and direct you where to look next based on the results.

Next would be looking at that joint connector for the ground. Verify that's not damaged, corroded, etc. and providing a good ground.

Is there any way for you to verify the instrument cluster itself? Like a speedo-healer maybe? That would be the simplest way to just see if it's reading properly. Otherwise, simulating the direct input voltage would test it at the cluster.

So, not that all that troubleshooting method is out of the way, I suspect you have a wiring harness issue since you have a previously crashed bike and getting codes 24 and 25 (speed sensor and gear position). I'd bet you have a pinched, crushed, or nicked wire somewhere that is dropping the signal voltage prior to it getting back to the ECU. Those things are a PITA to find and would require working your way up from the sensors to find that location. Tedious, for sure.
 

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Discussion Starter #6
Ok, so I checked couple things:

- The gray connector near gas tank seems fine and it has proper ground, at least the BK/Y cable
- Input voltage to the sensor is almost 5V
- Ground is also correct at the sensor
- Output with turning wheel is 0V doesn't change with spining

I did notice that my previous measurements on the output/input have been incorrect because the wires have been pulled of the main gray connector and are run next to it (picture in first post). The previous owner mixed up the cables and the sensor was given improper ground/input voltage. If I'm correct that has probably damaged the sensor itself? I tested both the old and new sensor and they have the same measurements.

Time to replace the sensor again?

Thanks
 

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Ok, so I checked couple things:

- The gray connector near gas tank seems fine and it has proper ground, at least the BK/Y cable
- Input voltage to the sensor is almost 5V
- Ground is also correct at the sensor
- Output with turning wheel is 0V doesn't change with spining

I did notice that my previous measurements on the output/input have been incorrect because the wires have been pulled of the main gray connector and are run next to it (picture in first post). The previous owner mixed up the cables and the sensor was given improper ground/input voltage. If I'm correct that has probably damaged the sensor itself? I tested both the old and new sensor and they have the same measurements.

Time to replace the sensor again?

Thanks
From that diagnosis, it does sound like the sensor is bad. If the wiring was screwed up, it could burn up the sensor. But you should definitely be getting more than 0Vdc out of the sensor while spinning the wheel like that.
 

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Discussion Starter #8
3rd sensor now and 0V are outputed from the speed sensot . WTF?!?! I have no idea what can be wrong:dontknow:

Help :sad:
 

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Discussion Starter #9
The thing that keeps on worrying me is the fact that both the ECU and gauges provider small amount of voltage on the BL/Y cable (sensor output cable). Is this correct? Maybe this extra voltage has damaged the 3rd sensor?

Sensor unplugged, ECU and gauges connected show 1.7V on that BL/Y cable.
 

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Discussion Starter #10
So this morning I bypassed the whole harness and just provided the sensor with 5v and ground and while turning the wheel, I would get a reading between 0.30V to 0.7V this would fluctuate.

Thanks
 
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