Polar 115 emc err 88

Good day members. Please assist. My polar 115emc starts up normal. A zero comes up on the display then changes to err 88. Checked safety bolt limit an voltages. Need some expert advise please.

 

Hi sir:
Please do the next:
1) Measure Aprox +42Vdc plug: CU 9.2+CU9.3
2) Check for mechanical Stiffness in its movement.,use Graphite for Lube very well.
3) test the Monitors Sensors S.SB , and see in your schematic diagrams for +24Vdc Plug: CU 9.6 +CU 9.4