If there is no G in the panel's name, there is no ground fault detection and the panel does not have an S4 pin.
If it has a single G in the name it has the chance it could be enabled if S4 is latched and under area 5 silent alarm relay there is a value other than 0.
If it’s a GV2, GV3 or GV4 and S4 is latched, ground fault detection is enabled.
If there is ground fault detection, latch S4 and measure DC voltage on Terminals 9 and 10: You should get 6.5-6.8 VDC Steady (not jumping around) when there isn't a ground fault.
If there is a ground fault it can take up to a minute to display and clear at the keypad.