FMI 758 CAT Fault Code
Unexpected Overvoltage Control Rectifier Activation
Cause :
Malfunction in the thermostat control system. The on-board computer reports problems with communication with the control unit, so a possible cause may be poor contact. The cooling system circuit is open, which may affect the operation of the power unit as a whole.If serial data communication is lost between any of the LIN devices on the LIN bus network, the master control module will set a no communication code against the non-communicating LIN device. The Diagnostic Trouble Code (DTC) sets when a supervised periodic message that includes the transmitter device availability has not been received.
Don't forget ! When a fault code pops up, CAT's Uptime Center is automatically notified via an cellular link, and it alerts the truck's owner by prearranged methods, usually email or phone calls.