Input Turbine Speed Sensor Location
 

I have a 2000 Volvo V70 XC AWD and have the PO717 input turbine speed sensor circuit no signal and P1618 TCM error codes. The car goes in and out of limp mode and the check engine light remains on. I notice no difference in the cars performance either way, idles fine, shifts smoothly everything seems to be normal. I suspect the sensor or the wiring to the sensor to be the issue. Can someone please help me with information about the sensor location. Is it internal or external to the transmission or is there something else I should check out first I plan to verify the resistance of the harness before I replace the sensor.