Ok, assuming the Cat is the same as the Doosan which it more than likely is. It sounds like the problem is in either the logic card or the base drive circuit (which is located on a seperate small pcb board). The base drive consists of 3 transistors T314, T315, T316. T316 gets it's base signal from the logic card, a 1.5V pulse, pin P12-5. This turns on T316 causing the other 2 transistors to turn on. So check the 3 transistors, in particular the base emmiter, and collector emmiter. These transistors are very cheap to replace. Check for a pulse from the logic card.
Regarding the power transistors T1D&2 theses are darlington transistors and must be changed in pairs as they need to matcched otherwise you can get thermal runaway which will destroy one of the power transistors.

well at this point the only thing i know to suggest is to run a 'self diagnostic' on the machine manually using the 'onboard' diagnostic.
This is the manuals suggestion when there are no error codes present on the display but no machine operation.

It is a fairly simple test routine using the 'run/diag' switch on the logic unit.

-disconnect battery
-remove logic cover
-discharge head capacitor bank
-remove drive fuse
-release parking brake
-place 'run/diag' switch in diag mode
-reconnect battery
-turn on key

there are several steps to test, if the step passes test it will advance on to the next step, if there are any failures it will not progress until you identify the fault and repair it. To skip a test step just toggle the 'run/diag' switch and it will skip the current test and move on to the next test.

on the inside of the rear cover is a truck diagram sheet which should include the diagnostic steps telling what each one is.
If the truck does not advance to the next step on any of the tests that circuit must be repaired.

When the accelerator pedal depressed no changes in the display, it is showing 9 only which is battery condition. even selection of direction also no changes in display code.

even when you depress accelerator pedal no code comes?
it will not show codes until direction is selected and pedal is pressed.

serial no. 9MC00480
Model F50D
LED showing the battery condition
No error code or flasing

Thanks for your information
I have changed the T1D & T2D transistor with new one
even then the same condition
There is no changes in LED indication
No fault code.
When the by pass contactor ON the trucks moves very fast again the contactor getting OFF but truck running.
Any other solution to solve the issue

Probably a failed drive transistor T1D or T2D or something else in the speed control since it works in bypass, that pretty much tells you your contactors, cables, and motor are functional. If you don't have service information on this machine try to do a comparative analysis with the transistors and look for the odd man out. Use your nose they usually stink when they fail, if you find one that failed try to swap the pump transistor with the suspect transistor and see if the problem follows.

need 2 things
serial number of truck
look on dash display and tell me what the led is doing? what number? is it flashing?