I'm working on a John Deere 331G s/n 1T0331GKLKF349876. It won't rev up with the foot throttle or the throttle knob. Everything else seems to operate ok. It had some random codes, I don't think that any where active. I cleared them and now it has no codes. Not sure if that was the right thing to do or not. I'm kind of surprised that it does not have any fault code. Does any one have a wiring diagram download?
Is the foot throttle all the way up and not stuck part way?
I'm not sure, the machine is not at my location right now. I'll be going to work on it tuesday. Can you explain what you think may be going on?
If the foot throttle is stuck part way down due to corrosion or dirt, then the engine defaults to idle and until the foot throttle is brought back to the "at rest" position, there will be no throttle control. The controller has to see both throttles at rest. If you enter the monitor's service menu (press and hold the menu button for 5 seconds until SERVICE MENU appears on the screen), you can also see if one throttle or the other is no sitting at 0%. Another thing to check is for moisture in either the foot pedal connector or moisture in the remote start box connector. That can cause no throttle with no codes. The remote start throttle connector is a three pin connector on the right side of the frame (left side looking in) zip tied to the harness just below and maybe slightly in front of the HCU. It will have wires labelled P042B (red), E035B (white) and R005B (black). One last thing to check is the dial on the dash sometimes breaks the stop and the dial over rotates, causing the same situation. I think the over-rotation one generates a code??
Thank you, I will check those things when I go over there. I'll let you know what I find.
Just wanted to give an update in the 331G. I checked the throttle dial and the foot pedal and they both seemed to be ok. I got a manual for it and I have diagnostic software but it is not Service Adviser so it is a little different. The manual says the signal voltage should be 0.7v - 4.4 from idle to full throttle. I was able to look at live data and the dial was working within the right voltage range. Then I looked at the foot throttle data it was staying around 2.7v. What I found was corrosion at the foot throttle plug. There was voltage getting from the power wire to the signal wire. Once I cleaned the plug up it works fine now. Thank you for the help mg2361 .