TN sig is engine rpm sig at N3/4 ECU.
That code will pop if CTP sw is not closed or hanging up ..Check the slack on the cable [ sholud have just a little] , Clear code.
If it comes back , you ae looking for 5-12v at pins 34 and 37 at ECU with Throttle closed , key ON.
I doubt you will se that again after clearing.. it can come up if one lifts the throttle by hand under hood when working on car.