Dear expert of LG WF-F783PC (washing machine). i am using an LG washing machine model LG WF-F783PC.its giving a warning alarm after 3-5 seconds of operation (wash & spin mode)

Possible that the inlet flow is low , check the inlet valve and filter. Also try using the manual settings and if all the cycle works well then it is possible that the fault is with the controller unit or a possible errors from the level controller or the inlet valve.
It is best to remove them , check reset after cleaning.