I've been working on a yale erc050ghn48te that has an odd problem. When trying to drive forward the motor jerks terribly, and sometimes the backup alarm briefly sounds. It seems as if it is trying to run in both directions simultaneously. When traveling in reverse it runs normally. What's even odder is that if the lift pump is running it will run normally in either direction.
It does not display any fault codes during any of this. If it was jerking in both directions of travel I would think it was the encoder in the motor, and I would expect it to give a fault code.
My gut says its a controller fault.
Does anyone have any experience with a problem like this?
Is there a way to view control system inputs & outputs on the dash display, and if so how. Is that done?