Hello folks,
We've recently bough a Still R70-35 (Type 7048-50, YOM 2002) forklift truck with a problem that may be more serious than I initially tough. The machines is with Deutz 1012E motor with EMR.
Few seconds after start the engine goes full speed and the red light next to the hour meter on the dashboard turns on.
I checked the engine speed sensor, 6B17, looks OK, I am reading nice sinewave. I am thinking that the setpoint PCB(3A2) of the forklift is faulty. The board has 4 status LEDs: nominal speed request, low speed, high speed and VCC. After start the nominal, low speed and VCC are ON, but the low speed should be off, since the RPMs of the engine are probably above the maximum, not below minimum. I've checked the speed sensor connected to the generator, it show square wave, but strangely with some rather low voltage, about 2.5-3V peak. I've tried to replace it with generic induction sensor, the peak voltage went to 24V as I expect, but without change in the behavior of the engine.

The board also has 8 DIP switches for diagnosis. According to the manual the board provides 2 setpoints to the engine ECU, analog and digital(no idea why two), and they are both out of range, analog is 0V (should be 0.8-3.8), digital is 0.8V(should be 2.5-10.5).
Do you have any ideas what could cause the problem, the regulator board or may be the engine ECU itself?

Thank you!