Sienna AWD V6-3.3L (3MZ-FE) (2004)
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Engine Control Module: Component Tests and General Diagnostics
ECM POWER SOURCE CIRCUIT
CIRCUIT DESCRIPTION
When the ignition switch is turned ON, battery positive voltage is applied to terminal IGSW of the ECM and the EFI relay (Marking: EFI) control circuit
in the ECM sends a signal to terminal MREL of the ECM switching on the EFI relay.
This signal causes current to flow to the coil, closing the contacts of the EFI relay and supplying power to terminal +B of the ECM.
If the ignition switch is turned off, the ECM continues to switch on the EFI relay for a maximum of 2 seconds for the initial setting of the throttle valve.
Wiring Diagram
