Yanmar BY Series Service Manual page 240

Function Description - Engine Management System
1 – Engine Control Unit (ECU)
2 – Internal ECU Sensors (operating voltage
and ambient air pressure)
3 – Fuse (F2) 10 A
4 – Fuse (F1) 3 A - CAN Switched Power
5 – Fuse (F6) 10 A - Auxiliary Power
6 – Start Signal from Key Switch
7 – Fuse (F4) 30 A - ECU Switched Power
8 – Fuse (F3) 10 A - Fuel Supply Pump
9 – Fuse (F5) 20 A - Fuel Pressure Regulator,
Water-in-Fuel, Camshaft Sensor, and Fuel
Volume Regulator
10 – Circuit Breaker - 80 A (boatbuilder installed)
11 – Power to Starter Solenoid Primary Terminal
12 – Starter Relay K1
13 – Main Power Relay K2
14 – Fuel Supply Pump Relay K3
15 – Power to Fuel Supply Pump
16 – B+ to Water-in-Fuel Sensor
17 – Not Used
18 – Check Engine Indicator Output
19 – Fuel Rail Pressure Control Valve
20 – Fuel Volume Control (high-pressure pump)
21 – Fuel Injector No. 4 (4BY) or No. 6 (6BY)
22 – Fuel Injector No. 2 (4BY) or No. 2 (6BY)
23 – Fuel Injector No. 3 (4BY) or No. 5 (6BY)
24 – Fuel Injector No. 1 (4BY) or No. 3 (6BY)
25 – Fuel Injector No. 1 (6BY)
26 – Fuel Injector No. 4 (6BY)
Figure 12-5 shows a general schematic diagram of all ECU input and output assignments.
The ECU is supplied by Bosch and has a hardware specification of EDC 16. The base ECU software is
Bosch DDE 5. The engine control software is application specific version NSW 3.0, which is a
torque-based software structure. It is NMEA 2000 implemented and provides diagnostics through OBD
protocol.
The ECU monitors data from the various sensors and controls such functions as low-pressure fuel pump
operation, fuel injection pressure, fuel injection system volume, and the timing and volume of fuel injected
by the Bosch electronic fuel injectors. Throttle control is fly-by-wire meaning it is controlled by electric
signals from the helm. The throttle control is either analog or digital depending on the level of control
options installed.
The ECU also uses sensor inputs to monitor engine condition and will set a trouble code if a system or
sensor indicates a problem. In most cases, a Check Engine light will be displayed. The engine may or may
not run normally depending on the fault. If an engine coolant overheat is detected, for instance, the ECU
will reduce the engine power output and the coolant overheat indicator will illuminate. If an audible alarm is
installed, it too will sound.
1
NEVER connect any additional devices to F2. F6 may be used however, it is not switched.
BY Service Manual
1
- Ignition
ELECTRICAL AND ECU
27 – CAN Signal - Low
28 – CAN Signal - High
29 – Panel, ECU, and CAN Ground
30 – K-Line
31 – Neutral Start Switch (NC in neutral)
32 – CAN / Analog Throttle Jumper Fuse (3 A)
(remove for analog throttle application)
33 – Single / Starboard Selection Fuse (3 A)
(remove for starboard installation)
34 – Fuel Rail Pressure Sensor
35 – Fuel Temperature Sensor
36 – Subthrottle Sensor 2
37 – Subthrottle Sensor 1
38 – Oil Pressure Sensor
39 – Water-in-Fuel Sensor
40 – Camshaft Speed Sensor
41 – Crankshaft Speed Sensor
42 – Charge Air Pressure Sensor
43 – Charge Air Temperature Sensor
44 – Engine Coolant Temperature Sensor
45 – Ignition Power Input from Key Switch
(terminal X1-D)
46 – Auxiliary Power Output (terminal X1-G)
47 – CAN+ to Warning Indicator (terminal X1-H)
48 – Battery Power to Key Switch (terminal X1-B)
49 – CAN Signal Blocking Diode
50 – High Bench 1
51 – High Bench 2
12-13