Honeywell XnX transmitter with mA sensor optima plus

This detector is not behaving as it should . It is to detect methane gas . I discovered a 500ohms resistor connected to TB-1 {I-4(+MA) &I-5(-V)} . and I am getting an error with code F165 . And , the mode of connection is source mode . However , I noticed too that it doesn’t accept mA calibration . But , when the resistor was removed the error did not come up but it couldn’t pass the loop test done .