code 16
Traction Motor, Stall Timer
(the truck is being stalled over the expected time and truck shuts down)

the listed possible causes are:
- Stall current flowed more then set time in traction motor
- faulty traction inverter current sensor
- shorted harness wiring
- faulty traction inverter DSP card
- faulty logic unit

from an electrical standpoint one of the above things could be causing this failure
from a mechanical standpoint you should check the brakes and make sure they are not adjusted too tight. Tight brakes causing the lift to lock during travel can cause this, i would make sure the wheels are adjusted properly and also make sure the parking brake is not adjusted too tight.

Once you rule out the brakes and it may turn out to be an electrical problem you should call a cat tech to do further diagnosis on this unit to determine where the problem is.

what YOU can do is go into the rear panel on the back of the truck and locate the logic control card (a square/rectangle box with 4 or 5 plugs going to it) unplug each connector and apply some electric silicone grease into each plug and reinsert them, this should help with any moisture issues that may be getting into the plugs.
Also you can remove the DSP card covers on the main controller and unplug the leads (ribbon cables) and reinsert them.
Sometimes loose connections can cause issues like this.
If doing this does not solve your issue then once again i suggest calling cat and have them deal with this.

A4EC240543 is the serial number. The code being flashed is 16.

need to know a couple things
first what is complete serial number of machine
second what error code is it displaying on the display when this behavior happens, it may not stay up on the display when it starts running again but when the fault occurs it may flash up there for a sec.