ECM Power and Ground Circuit Check

ECM Power and Ground Circuit Check

Wiring Diagram

Wiring Diagram:

Circuit Description

When the ignition switch is turned ON, the main relay turns ON (the contact point closes) and the main power is supplied to ECM. And then ECM supplies 5 V power to each sensor (EVAP leak check pressure sensor, A/C refrigerant pressure sensor, APP sensor and TP sensor). If 5 V power circuit to each sensors from ECM is shorted to ground, ECM stops engine and emission control operation.

Troubleshooting

NOTE:
^ Before performed troubleshooting, be sure to read the Precautions of ECM Circuit Inspection.
^ When measuring circuit voltage, resistance and/or pulse signal at ECM connector, connect the special tool to ECM and/or the ECM connectors referring to Inspection of ECM and Its Circuits. Pinout Values and Diagnostic Parameters

Step 1-3:

Step 4-6:

Step 7-10:

Step 11-12: