Speedometer varying

[want2ride]

Ok Gentlemen, my 2009 FJR is having speedometer issue. Started a while back but has become a regular issue now. The speedometer will rev up to a much higher speed than what I am going. I could be doing 35 but the reading is 140. Now it even follows the RPM gauge if I rev it. Thought it could be the rear wheel sensor going bad so I replaced but the problem remains. What I missing on this issue?

 

[RossKean]

That's a new one to me - never heard of that on an FJR.
I assume that there is nothing such as a "Speedo-Healer" on this bike that corrects the speedometer readout?

I might try unplugging and replugging the ECU connector - look for corrosion or bent pins. Check the connector to the instrument cluster as well.

Other than that, I got nothing. Good luck.

 

[mcatrophy]

Ok Gentlemen, my 2009 FJR is having speedometer issue. Started a while back but has become a regular issue now. The speedometer will rev up to a much higher speed than what I am going. I could be doing 35 but the reading is 140. Now it even follows the RPM gauge if I rev it. Thought it could be the rear wheel sensor going bad so I replaced but the problem remains. What I missing on this issue?

I've never heard of this one before, but some thoughts:

I don't think it's likely to be a sensor issue, or the ABS system would be complaining. The sensor signal feeds directly into the ABS control unit. As far as I can tell, the ABS control unit tells the ECU what the speed is (whether it's a sensor frequency signal passed on or a coded speed message I don't know), this then tells the display unit the speed - I’m pretty sure with a coded message.

To me, the most likely cause would be within the display unit itself, but there's no certainty.

First action, as RossKean suggests, check all connectors associated with the ABS control unit, the ECU and the display unit.

 

[Ludwig61]

Ok Gentlemen, my 2009 FJR is having speedometer issue. Started a while back but has become a regular issue now. The speedometer will rev up to a much higher speed than what I am going. I could be doing 35 but the reading is 140. Now it even follows the RPM gauge if I rev it. Thought it could be the rear wheel sensor going bad so I replaced but the problem remains. What I missing on this issue?

Since it is following your RPM gauge, it is getting something from your tach feed. The ABS would object if one wheel was going faster. If the crossover affects the ABS-perceived speed of both wheels equally, then that can't be happening in too many places. Or the crossover is where it affects your dash speed without affecting the ABS-perceived speed. Not sure where those places would be.

I'm not sure how to proceed any further. I'm expecting this to turn out to be a computer issue.

 

[mcatrophy]

If it's of any help, below is the electrical schematic for the 2009 in which I've highlighted the path the speed signal takes to get to the display.

Circuit is copied from the Haynes manual, hope I'm not infringing copyright by offering it here. Probably the UK version, but no difference in the area we're talking about.

Circuit diagram, speed signal path highlighted​

Click on image for full size view

Original scan (two pages merged)​

(I would have shown the images here, but my website is having trouble with its security certificate. Hopefully my IT man can fix it shortly)

Edited to include clickable thumbnail.

 

[RossKean]

(I would have shown the images here, but my website is having trouble with its security certificate. Hopefully my IT man can fix it shortly)

With the recent upgrade, you can copy the image and paste directly into your forum post. Advantage is that it will remain no matter the status of the external source. Not sure if the wiring diagram would have enough resolution or not...

 

[mcatrophy]

With the recent upgrade, you can copy the image and paste directly into your forum post. Advantage is that it will remain no matter the status of the external source. Not sure if the wiring diagram would have enough resolution or not...
..

Yes, but as you say, resolution not really helping.

I'm suffering from a double whammy, my web site's certification, and the FJRforum site not accepting the "http//" url prefix, which would be served without issue.

 

[Wizard37]

The YCC-S speed sensor is mounted on the back of the crank case and reads the gear teeth pulses. Page 5-96 in my 2006 - 2007 service manual (Gen 2). I had a 2007 and now have a 2019ES.

 

[graytaz]

The YCC-S speed sensor is mounted on the back of the crank case and reads the gear teeth pulses. Page 5-96 in my 2006 - 2007 service manual (Gen 2). I had a 2007 and now have a 2019ES.

As I read it, the YCC-S (Yamaha Chip Controlled shifting) is for the AE model without the manual clutch. My read of the service manual for the A model is that the speedometer is directly fed from the ABS ECU as referenced in the ABS ECU electrical block diagram.

 

[mcatrophy]

The YCC-S speed sensor is mounted on the back of the crank case and reads the gear teeth pulses. Page 5-96 in my 2006 - 2007 service manual (Gen 2). I had a 2007 and now have a 2019ES.

As I read it, the YCC-S (Yamaha Chip Controlled shifting) is for the AE model without the manual clutch. My read of the service manual for the A model is that the speedometer is directly fed from the ABS ECU as referenced in the ABS ECU electrical block diagram.

graytaz is correct. Don't confuse the "YCC-S speed sensor" with the vehicle speed sensor. In all Gen 2 and above, YCC-S or not, vehicle speed is obtained from the rear wheel sensor.

The YCC-S speed sensor is for determining clutch engagement requirements and stuff, not directly connected with vehicle speed.

 

[graytaz]

graytaz is correct.

Hang on, I've got to get my better half to read that.

 

[want2ride]

I've never heard of this one before, but some thoughts:

I don't think it's likely to be a sensor issue, or the ABS system would be complaining. The sensor signal feeds directly into the ABS control unit. As far as I can tell, the ABS control unit tells the ECU what the speed is (whether it's a sensor frequency signal passed on or a coded speed message I don't know), this then tells the display unit the speed - I’m pretty sure with a coded message.

To me, the most likely cause would be within the display unit itself, but there's no certainty.

First action, as RossKean suggests, check all connectors associated with the ABS control unit, the ECU and the display unit.

Thanks for all the pointers on this issue. Now I just have to find the time to get out there and chase it down. My wife fell down a flight of stairs leading to a bimalleolar fracture. Surgical repair is scheduled. Between her care and 14 hour shifts at work my time is greatly limited.