Arduino and FTDI Communications
Yes, see here for the schematic of the sparkfun FTDI breakout. 

As you can see on the far right, the FTDI connector has 6 signals, two of which are RX and TX. Those are the ones you would want to hook your Arduino's UART pins to. However, depending on the complexity of the diagnostics program (the computer program you are supposed to use to issue the commands and parse the responses), it might be simpler to just pony up and buy something like the product I linked to.