The symptoms of either when pooched are pretty much identical, especially for the setup where the TFI module is mounted to the Distributor rather than remotely on the fender well. This test is for that Distributor mounted set up.
Although When either pooches. It's recommended to replace both. Also, they share the same power & ground circuits. You can also take your TFI in for bench checking & a failing PIP sensor usually generates an Error code. No specific code for TFI, but sometimes a SPOUT circuit code is actually related to the TFI, if no problem w/ the Spout circuit is located otherwise.