Component Tests and General Diagnostics

ECM Power Source Circuit

DESCRIPTION

When the ignition switch is turned to the ON position, the battery voltage is applied to terminal IGSW of the ECM (Included in HV control ECU). The ECM MREL output signal causes a current to flow to the coil, closing the contacts of the IGCT relay and supplying power to terminal +B of the ECM.

If the ignition switch is turned off, the ECM holds the IGCT relay ON for a maximum of 2 seconds to allow for the initial setting of the throttle valve.

When the ignition switch is turned ON, voltage from the ECM's MREL terminal flows to the IGCT relay. This causes the contacts of the IGCT relay to close, which supplies power to terminal +B or +B1 of the ECM.

Wiring Diagram:

Step 1-2:

Step 3-4:

Step 5-6:

Step 7-8:

Step 9:

INSPECTION PROCEDURE