The TCON is not sending the voltage to the 2 speed solenoid coil. end to end wiring are fine.

Hi Syed,
after looking at the service literature this unit is controlled by a canbus system so whatever the platform does it goes through the canbus and tells the TCON what it wants and then the TCON instructs the components selected to operate. So there is a white with red stripe wire and a red with white stripe wire that are related to the 2 speed circuit and brake release circuit that go from the ground box through the harness going to the 2 speed/brake release valve mounted on the frame on one end of the unit. This is a small block with 2 solenoids on it. The block should be clearly marked as to which solenoid is the brake solenoid and which one is the 2 speed solenoid. Check the power supplied to the 2 speed valve when high speed is selected and drive is requested and brake is released. The 2 speed valve should be getting the signal to change the fluid mode to put the motors in high speed mode.
If your signal voltage is low or not present at the solenoid then you will have to back probe the circuit and find where it is loosing continuity if this is the case.
There may be other reasons but lets start here.
If you want the service literature you can find it on genie's website, it is free to the public no charge. Just pay close attention to the model number and serial number when selecting the one that goes with your machine.

I have checked as per your instructions, unfortunately not found any error in "active machine fault". But following errors found in error history.
15-19 at 292.86 Hrs
11-19 at 292.52 Hrs
35-19 at 287.07 Hrs
77-21 at 271.78 Hrs
76-21 at 271.78 Hrs
76-13 at 267.48 Hrs
24-36 at 267.48 Hrs
72-21 at 267.48 Hrs
Turtle to Rabbit switching also showing on ground control panel when changing it via toggle switch from platform. Further more I've disconnect the positive wire from 2 speed solenoid coil and supply the positive voltage separately from the jumper wire then drive it in high speed mode, it travels fine which means the voltage is not coming from the circuit in normal operation. Do you have any idea please advise.

Thanks for your advise, I'll let you know

first thing you need to make sure of, is that the boom and extend are fully stowed. (boom all the way down and extension section is retracted).
Check the display for any active faults during operation when this condition is happening. (will need someone else to watch it while unit is being driven).
If the engine is laboring in high speed mode only there could be a problem in the 2 speed valve but first things first, check the things i advised on first before jumping to something else prematurely.