Ok. It is a E16 right? Is it a 324 or 335?

Check accelerator. When it is not in neutral in the first seconds after starting up you have slow drive. Try push and lift the pedal a little bit directly after start up.
Might also be the speed sensor, that is on brake disc of the right motor.
On a 324 the temp sensor might not give a light. This year linde trucks don't have error message on the display too. The temp sensors are variable resistors. Not temp switches.