jcb JS130, Service Manual

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4 - 14
Section C Electrics
9803/6410
Section C
4 - 14
Issue 1
Engine Control
Detection of Throttle Motor Assembly Defect (Out-of-step)
Fault
When the pulse signal cannot be interrupted by the driver, and deviates from regular rotation.
Possible Factors
1. If the adjusting screw of the throttle link is loosened, and the length of the link is changed more than the deflection of
the spring.
2. If the key switch is ON (also during running), and the throttle motor rotates by abnormal external force and shifts to
the stop position.
Out of step detection
(Safety device works to protect throttle motor from breakage when above problem occurs.)
1. After the key switch is ON , the limit switch of clockwise direction (stop position) is not turned on after 2 seconds.
2. After the key switch is ON , the clockwise limit switch is turned on and afterwards even though the key switch is not
turned OFF or the emergency stop switch is not pressed, the clockwise limit switch is turned ON again.
Any of the above conditions will stop the drive of the throttle motor, and 'electric system abnormality' is displayed on
the message and '0000' is displayed on the clock.
Check the throttle link position first if the above is displayed. Refer to throttle link installation procedures.
Engine Reverse Rotation Prevention
If the engine goes into a reverse rotation, this feature will stop the engine in order to protect it and the hydraulic circuit.
When the engine changes to reverse rotation from forward rotation, the engine oil pressure decreases. Twelve seconds after
the engine has been started, the pressure switch turns on for 3 seconds and the throttle motor is moved to the engine stop
position.