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Engine
Main relay is controlled by ECM, when turning the ignition
switch to "ON" position, battery voltage passes through the
ignition switch to ECM 10 A fuse, and finally to ECM harness
connector EN01 terminal No.17. ECM detects the terminal
voltage, then controls the EN01 terminal No.32 to connect to
ground. The main relay starts work and provides power to the
Air-Conditioning compressor relay, cooling fan low speed
relay, cooling fan high speed relay, pump relay, ECM wiring
harness connector EN01 terminals No. 8 and 51, Canister
solenoid valve, VVT solenoid valve, ignition coil, fuel injectors,
Pre-Catalytic oxygen sensor heating, Post-Catalytic oxygen
sensor heating and vehicle speed sensor. So when the main
relay is not working properly, the engine will not work. ECM
controls the main relay through ECM harness connector EN01
terminal No.32. ECM will not record the main relay associated
DTC code.
7. Pump Relay (I) and Fuel Pump
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Pump relay is located in the underhood fuse box. fuel pump is
installed in the fuel tank. ECM controls fuel pump relay closing
and the fuel pump work. The fuel pimp and the motor are
installed on the same axle inside the housing, and surrounded
by fuel, cooled and lubricated by fuel. As the pump relay pulls
in, battery provides power through fuel pump relay to fuel
pump. Only when fuel pump relay is working and the engine is
running, the electric fuel pump circuit is connected. When the
engine stops running due to an accident, the fuel pump
automatically stops. The electric fuel pump export maximum
pressure is determined by the pressure relief valve installed on
the fuel pump. The export maximum pressure is between 450
kPa and 650 kPa. Fuel system uses "no-return pipe system",
which stabilize fuel pressure at around 400 kPa. ECM controls
fuel pump relay through ECM harness connector EN01
terminal No.61. If the pump relay and its circuit are faulty, DTC
code P0627, P0628, P0629 will be recorded.
EF28
EF27
EF08
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5 3
G
2
30
EF01
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I
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FE02-5136b
8. High-Speed Cooling Fan Relay (A), Low-Speed
Cooling Fan Relay (B)
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Two cooling fan relays are in underhood fuse box, mainly used
to control the high-low speed cooling fan operation. ECM
controls the Low-Speed cooling fan relay through ECM
harness connector EN01 terminal No.62. ECM controls the
High-Speed cooling fan relay through ECM harness connector
EN01 terminal No.52. when the cooling fan relay and the circuit
are faulty, DTC code P0480, P0481, P0691, P0692, P0694 will
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be recorded.
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9. Air-Conditioning Compressor Relay
30
Air-Conditioning compressor relay is located in I/P fuse box,
and is an internal integrated type. It is mainly used to control
the electromagnetic compressor clutch work. ECM controls Air-
Conditioning compressor relay through ECM harness
connector EN01 terminal No.60. when the Air-Conditioning
compressor relay and the circuit are faulty, DTC code P0645,
P0646, P0647 will be recorded. If the relay is damaged, only
replace the I/P fuse box.
10. CAN Information Output
ECM sends information to other modules with CAN signals
through the CAN network, to achieve network sharing, the most
typical signals are: TPS, ECT, engine speed signals and so on.
CAN_H signal communicates with other CAN network modules
through ECM harness connector EN01 terminal No.33. CAN_L
signal communicates with other CAN network modules through
ECM harness connector EN01 terminal No.34. If ECM
communication with other modules fails, DTC code U0001,
U0121, U0140, U0151, P1523 will be recorded.
EC718/EC718RV EC715/EC715RV 10/2009
Control System JL4G18-D
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EF28
EF27
EF08
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1413 12 11 10
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30
9
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6
5
7
85
4
3
2
1
FE02-5137b
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