[Madfast2791]

Hey guys, just bought a 03' 650 Rincon to use on my farm with transmission/shift issues. I'm relatively new to ATV'S but mechanically inclined. Any help is greatly appreciated.
So here's what I know at the moment:

1. Speedometer does not register and stays at 0 when driving and nothing flashes when ignition is turned to on position. (all features/indicators work properly as well as the gear indicator)
2. when in auto mode motor seems strong and ATV runs well but does not shift up or down.
3. When in ESP mode trans shifts up thru 3rd and down to 1st as should but the ATV feels sluggish.
4. When prompted by turning on the ignition and holding shift buttons the fail test code flashes 11 times referring to the TPS. (I have went through all the checks per the service manual and everything checks fine with the TPS)
5. Man I bought it from said that everything worked fine until he had a man rebuild the carb(spreedo/trans was working/shifting). He is a friend so I believe him to be honest as to what he has told me.
6. ALL TEST WITH THE TPS HAS LEAD ME TO THE ECM being bad, but before I go to purchasing one I would like a little help or insight and other areas that need to be addressed.
7. Could it be a VSS issue? I do not have a code flashing for it.

 

[Madfast2791]

So after reading a few post today I decided to delete the code 11 / faulty TPS after trouble shooting it yesterday(still not sold on a bad ECM). It now has no codes flashing when prompted. I decided to drive the ATV. It does not prompt that there is a issue upon initial start up and it does not shift in auto while riding but feels responsive and moves well in the gear that it's in. ESP shifts 1 thru 3 and feels a little more responsive. Speedometer still does not register my speed. VSS ISSUE WITH NO CODE POSSIBLY????
I will start trouble shooting the transmission next.
Any advice is greatly appreciated.

 

[JeffinTD]

I think I’d be looking at VSS and related wiring first. A transmission issue wouldn’t cause the speedometer not to work, but a problem with the speed sensor could prevent the transmission from upshifing in auto mode.

The part that doesn’t make sense to me is it hasn’t set a code.

Anyway, I think if it were mine I’d check out the rear VSS, since it would be pretty simple. It looks like you could unplug it and make sure voltage is present across the + and - wires when key is on. Reconnect, put it on a jack, and probe the signal wire. Should have 5v pulses when wheels turn.

 

[Madfast2791]

I think I’d be looking at VSS and related wiring first. A transmission issue wouldn’t cause the speedometer not to work, but a problem with the speed sensor could prevent the transmission from upshifing in auto mode.

The part that doesn’t make sense to me is it hasn’t set a code.

Anyway, I think if it were mine I’d check out the rear VSS, since it would be pretty simple. It looks like you could unplug it and make sure voltage is present across the + and - wires when key is on. Reconnect, put it on a jack, and probe the signal wire. Should have 5v pulses when wheels turn.

Thanks Jeff,
I've done some trouble shooting on the VSS already as far as testing the voltage and It was good. My next step will be checking for the pulse voltage. I would have already done it but I've been looking for a diagnostic tool that I thought one or two of my boat mechanics may have, but no such luck. So I guess I will probe the wires in hopes that something will turn up there. My first suspicion was the VSS, until I seen the code for the TPS. I found one cheap so I plan to swap it just to kill that avenue completely even though I have already checked it for failure and reinstalled it / initial set up and code wipe. I have also been checking grounds which seems to be a ghost for many, but it has not produced any fortunes for me at this time. I'm really hoping that it is a faulty VSS, but with no codes I am not sure. Kinda hoping someone has had the speedo problem with a fix. Maybe something will turn up soon

 

[Madfast2791]

Ok,
So today I did some more trouble shooting on the VSS and I think there is definitely an issue with it.
Per the service manual:

1. STEP 3 voltage between BG + / Gnd - test for 10v = YES
2. STEP 4 voltage between BG + / GR - test for approximately 5v = 4.56v was the measured value / I wouldn't think .44v would be an issue or would it?
3. STEP 5 Check for 0 to 5v pulse voltage. I do not have the inspection tool that is called for so I probed the wires of the VSS needles. = measured voltage was a constant 4.56v to 4.59v with very little change while turning my rear wheels in neutral at various different speeds.
4. Still no codes being sent

 

[JeffinTD]

I would think you are to the point where you could try replacing the sensor without being accused of blindly throwing parts at the problem.

I am curious about it not throwing codes. I wonder if it sets code when front and rear VSS don’t agree for a period of time? If so, if the ECM wasn’t getting signal from either front or rear... which would make me wonder about something not fully plugged in, corroded or damaged harness, or the reference voltage shorted to ground on one may pull the voltage down on the other.

Anyway, it would be interesting to see what you get from the front VSS. If you knew someone who had a pico scope or other automotive oscilloscope...

 

[Madfast2791]

I would think you are to the point where you could try replacing the sensor without being accused of blindly throwing parts at the problem.

I am curious about it not throwing codes. I wonder if it sets code when front and rear VSS don’t agree for a period of time? If so, if the ECM wasn’t getting signal from either front or rear... which would make me wonder about something not fully plugged in, corroded or damaged harness, or the reference voltage shorted to ground on one may pull the voltage down on the other.

Anyway, it would be interesting to see what you get from the front VSS. If you knew someone who had a pico scope or other automotive oscilloscope...

I have ordered a new TPS and Rear VSS. I plan on changing the TPS to see if there is any change and I like to have on hand spare parts as well. The VSS I am sure is bad, but I don't know if the front and rear have to be in agreement while moving in 2WD. I do know that the 4WD indicator is supposed to flash when operating in 4WD and then it supposed to send the code, which I have not seen it do. I will post an update as soon as the VSS and TPS have been installed and set up.

 

[Madfast2791]

Replaced the Rear VSS (surprisingly it was here in 3 days)

1. Speedo works
2. still doesn't shift
3. codes are now being sent
4. code 5 is what has been displayed
5. onto front VSS, I'm curious as to whether or not I can just disconnect it at this point??

 

[Madfast2791]

Replaced the Rear VSS (surprisingly it was here in 3 days)

1. Speedo works
2. still doesn't shift
3. codes are now being sent
4. code 5 is what has been displayed
5. onto front VSS, I'm curious as to whether or not I can just disconnect it at this point??

1. disconnecting the front VSS did not improve any end results
2. diagnosed the front VSS today and it proves to be faulty.
3. My guess is that when both front and rear go bad the ECM can not determine what the faulty sensor is.
4. moving on to change the front VSS and update as soon as possible.

 

[Madfast2791]

Replaced the front VSS today and it is now shifting gears. Shift points seem a little odd.
at WOT it shifts from 1st to 2nd at 18mph and it really sounds like its over revving.
If I hold off the throttle say 1/2 to 3/4 throttle is seems to shift at a lower point and fills much better.
It actually shifted thru 3rd gear today while riding. think I was around 30 mph. Curios what the top speed should be and what the shift points to be??