Diagnostics help point you to a problem area but cannot always specify exactly what's at fault.

Use a ground wire or a (non self-powered) test light clipped to the intake manifold and, with the TPS connector unplugged and a timing light aimed at the timing marks, touch the #1 pin (orange wire) and look for a 10°-15° jump in timing as you make/break the connection. If the timing is affected, the signal is definitely getting to the ECU. You may simply have a bad ground (#2 wire) or a borderline adjustment which doesn't close the microswitch every time.

No timing change indicates the code is correct and you were on the right track.

Find a helper as you'll need 3 hands.