ECU code 51

I have a '92 Corolla with the check engine light flashing the code 51. I looked up and here's the description for the code. Can anyone explain to me what it all means? How do I fidx the problem? thanks


SWITCH SIGNALS

IDL (tps) CONTACTS OFF, NEUTRAL START SWITCH OFF, A/C SWITCH "ON" SIGNAL TO ECU

WITH DIAGNOSTIC CHECK CONNECTOR SHORTED

--A/C SWITCH/CIRCUIT

--A/C AMPLIFIER

--TPS/CIRCUIT

--NEUTRAL START SWITCH/CIRCUIT

--ECU