I am currently having a strange issue with my Kobelco. Upon turning the key on the throttle stepper motor goes into a strange fit. It keeps pushing the injection pump lever all the way down to engine stop, hits the stop screw on the pump and bounces back to about the low idle position. It does this about 10 or so times then stops moving and the CPU light begins flashing. Also getting readout E21 on the CPU behind the seat. Bad stepper motor or maybe out of adjustment? If it's out of adjustment is there a procedure to recalibrate the darn thing! Any help would be greatly appreciated! Also the machine serial number is LF04-02060
Harry160G: Unfortunately, I can't offer any help on your stepper motor problem...but I have a question...I have a 2005 NH EH80 CS, which is really a Kobelco sk80cs, build # LF 04-02072, which is VERY close to your build #. Do you have a shop manual for your Kobelco?? Or do you know where to get one at a reasonable price?? Hard copy or electronic. I would be interested. Re your stepper motor problem, have you tried Mr. Kobelco on his separate, paid forum (see ), or GRANDKOBELCO on this HEF??
Harry160G: Just found Mr. Kobelco's forum, but the site link won't display correctly in this post. So, just google "Mr. Kobelco" & follow the link to "hf-hydraulics". StumpyWally
E21 is governor motor start point error. In the step motor is a limit switch which tells the cpu the start point. If this switch is faulty or if one of the wires in the two wire connection is broken the motor cant find its position.