Relationship Between Open/Short Circuit and the ECU Pin Control

Relationship Between Open/Short (high Resistance) Circuit And The ECU Pin Control: Case 1:

System Description: When the switch is ON, the Electronic Control Unit (ECU) lights up the lamp.

Input-output Voltage Chart:

If high resistance exists in the switch side circuit (caused by a single strand), terminal 1 does not detect battery voltage. ECM does not detect the switch is ON even if the switch does turn ON. Therefore the ECM does not supply power to light up the lamp.

Relationship Between Open/Short (high Resistance) Circuit And The ECU Pin Control: Case 2:

Input-output Voltage Chart:

^ If high resistance exists in the switch side circuit (caused by a single strand), terminal 2 does not detect approx. 0 Volts. ECM does not detect the switch is ON even if the switch does turn ON. Therefore, the ECM does not control ground to light up the lamp.