Ecm Relay Circuit Operation; Key Power; Shut Down - International VT 275 V6 Manual

PDC# Device
F4 30A...IDM/ECM
F12 20A...RUN/ACC
F41 10A...ECM PWR
F46 5A...ECM KEY PWR
R ECM RELAY - POSITION 50
1
BATTERY
STARTER
MOTOR
RELAY

ECM Relay Circuit Operation

• The ECM controls its own power up
and power down process. When
the key is OFF, the ECM stays
powered up for a brief period. The
ECM then powers down after
internal housekeeping functions
have been completed.

Key Power

• The Run/Accessory position of the
key switch receives battery voltage
from the Power Distribution Center
(PDC) fuse F-12. When the key is
ON, the switch supplies battery
voltage through fuse F46 to ECM
pin X3-3. Battery voltage
available at all times through fuses
F4 and F41 to ECM relay pins 1
and 3. The two fuses are in series,
with F4 feeding both the IDM and
ECM relays, and F41 dedicated to
protecting the ECM circuit alone.
Pin 1 supplies voltage to the
relay coil.
X1 X1
ECM
X2 X2
X3
X3
X4 X4
200 A F4
F41
F-46
KEY SWITCH
F-12
• Pin 2 connects the coil to pin X3-5
of the ECM.
• When the key is ON, voltage
supplied to pin X3-3 signals the
ECM that the operator is going to
start the engine. The ECM then
supplies a ground circuit to pin X3-5.
When this occurs, current flows
through the ECM relay
creates a magnetic field causing
the relay to latch. When latched, the
relay connects pin 3 to pin 5 and
supplies current to the ECM
through pin X4-1 and X4-2.
is
International ® VT 275 V6 Engine
ELECTRONIC CONTROL SYSTEM
X3-3 V
IGN
X3-5 ECM MPR
X4-1 ECM PWR
X4-2 ECM PWR
PDC
TO
TO IDM RELAY
ENGINE
INLINE
12-WAY
R
1
3 5
1 2

Shut Down

• When the key is OFF and voltage is
removed from ECM pin X3-3, the
ECM shuts down the engine but
keeps the ECM powered up briefly
until the internal house keeping is
completed.
coil and
27