Troubleshooting a speed sensor problem
I am trying to troubleshoot an intermittent problem with what I think is the front speed sensor on my 2006 Rincon and would like some opinions. The problem mainly happens while stopped (but it has occurred while moving slowly) and the speed on my Rincon starts jumping erratically 57mph, 3mph, 80mph, 5mph, etc... and the anticreep function disengages. I have had it happen three times this year during my now 15 rides this summer. The first time I was riding a very difficult (dry) rocky trail (I ripped my CV boot on this ride). The second time I was stopped waiting for other riders to catch up (also dry). And the I had gone through a couple of streams and was waiting for other riders to catch up. It is pretty annoying when it happens because it will cause the speed governor to kick in and kills the engine. The DTC blinks one long and two short which indicates code 12 (front VSS no signal).
The other night while I decided to troubleshoot the front speed sensor using service manual. While I was at it I thought I would try to recreate the failure by disconnecting the front VSS. When I disconnected the front senor I ran the engine for a minute I was unable to get it to throw code 12. In fact I was able to drive around like normal placing it into 4wd and shifting gears and the speedometer was working. Ok I thought that was a bit strange so I also disconnected the rear speed sensor and again I was able to drive around like normal just that the speedometer wasn't reporting any speed. Next I reconnected the front sensor and I could drive around but I received no speed on the speedometer. As far as I can tell everything checks out (voltages and signals from the sensors).
At first I was thinking I had a bad front sensor but it appears that it might be caused from the rear as it appeared the rear is used to report the speed. Has anyone seen this behavior and or symptoms before?
One thing to note: On the last occurrence I started tearing into things a bit and noticed that the ECU below the handlebars and next to the storage box was hot (mainly from the engine heat coming off the radiator) Could it be possible that the heat could be contributing to the problem?