P1780 is returned when the PCM doesn't see the OCS (Overdrive Cancel Switch)
activated during the quick test. This could result from a switch or wiring
concern or be the result of an improperly performed test. During the self
test, you will be requested to activate one or more inputs.... if the PCM
doesn't see a "change of state" in the circuit, it will flag a code.

When we are requested to activate an input, we need to be sure to allow
enough time for the PCM to see the condition since the processor cannot
monitor all of the inputs all of the time..... It, instead, looks at each
input briefly in a rapid cycle. Some inputs may get checked several times
during this cycle while other inputs may only get scanned  once.

HTH