Tip for the future with Linde trucks is, post up the start of the serial number to pin point the series & year.

From the info already provided its either going to be a H2X 392 or a 393, the letter after the 3 digit series number gives the year of manufacture, year is also on the data plate.

L = a lift fault ( smart these German's )

L222 = Joystick for more than 2 sec not in neutral position after Power On.

If it has a key switch fitted, check the contacts & switch, sounds like its very briefly powering down & back up again which in turn throws the error code.

Check the hydraulic joystick's & the wiring to them would be a good place to start.

If you have the 4 way joysticks fitted also check the rubber cover with the symbols on hasn't come loose from the console as this can stop the joystick returning to neutral position.