M59 will not drive

[TBarD]

Well you could actually have a HST problem, but the symptoms suggest it may be a simpler (and much less expensive) electrical problem instead, so that would be the first thing to look for. The ECU (computer) controls everything. The HST pump is directly connected to the engine via the clutch. Flow to the HST motor is controlled by a servomechanism that is controlled by the ECU. When you move the foot pedal the ECU is sending signals to the servo which moves a swash plate. The swash plate controls flow to the HST motor, providing forward or reverse and speed control, all by controlling the flow of hydraulic oil. The bottom line is, probably either the ECU is not saying go for some reason, or (less likely) you could conceivably have a problem with the HST servo. The first thing to do is check for error indications from the ECU, after which you would have to start running diagnostic tests.

 

[TBarD]

Be sure to check the console when you first turn the key, for any messages like ERROR-XX. The ECU checks a lot of sensors and should report any basic errors (and of course if its not happy, you aren't going anywhere or it might even turn off the engine!).

 

[BandDcabinet]

Auto throttle is a mechanical cable

Travel pedal sensor provides feed back to the ECU.

I would start there. Perhaps you will be lucky and find the connector loose.

Let me know if you would like further info..

Regards

 

[BandDcabinet]

Further diagnostic details. I have the elec schematic. In general it shows sensors attaching back to the ECU.

Regards

 

[MisterE]

Thanks tbard for the hst transmission explanation. I've been ignorant of how they work and that makes a lot of sense. Got a mechanic that's going to check it out thus evening. Its not giving me any error codes which I find strange.

Thanks band d cabinet for the electrical diagrams will definitely put them to use.

I'll be sure to let y'all know how it turns out.

 

[BandDcabinet]

One of the pictures walks you thru testing. Have you been holding down the two buttons when you switch it on?

 

[MisterE]

Btw, where is the ECU located?

 

[BandDcabinet]

See attached

I would run thru Test Mode A and check the feedback from various sensors. In particular T10 and T11.

Don't hesitate to ask for more info. My binder is 5 inches thick!!!



Regards.

 

[MisterE]

T10 and t11 check normal. T12 and t13 do not respond.

 

[ultrarunner]

Just a shot in the dark...

My Deere 110 did the same thing and I found a $60 sensor on the bell housing to be the problem...

It would start... just no movement with the pedal forward or back.

Relieved it was something simple and not expensive!