2016 - 2017 model year Sonata LF HEV vehicles contain a Power Relay Assembly. The PRA is equipped with a main relay and High Voltage Cable, which in some instances may have a loose connection. If the vehicle continues to operate in this condition, a loose connection could cause a no start condition or a Check Engine and Hybrid Warning Light On with either or both of these DTCs stored: DTC P1B77 High Voltage Battery Precharging Fault DTC P1990 Oil Pump Unit Input High Voltage Wiring Line Open This bulletin describes the procedure to inspect the PRA, High Voltage Cable, and main relays and replace them if necessary.
