Where are the UART Rx and Tx pins on a dsPIC33FJ32MC202?
Further to Keelan's answer:

The official name for the technology is "peripheral pin select" or PPS.



The 4th column in table 1-1 is the PPS column. You can see that the UART pins are all listed as 'Yes' which tells you that you need to use PPS to get these functions physically connected to pins.

Table 4-16 lists the input register map: file RPINR18 concerns the UART receive function. The value you write to RPOR18's low byte will determine which pin acts as UART receive.



Table 10-2 lists the output registers for PPS. UART transmit is 0x03; you would write 0x03 to the RPOR register corresponding to your desired output pin to connect it to UART transmit.