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System Information of Volvo Diesel Engine

Apr. 27, 2018

Altitude correction


The control unit is fitted with an atmospheric air pressure sensor and an altitude correction function for engines operating at high altitudes. This function limits the fuel volume in relation to ambient air pressure. This is to prevent smoke, high exhaust temperature and to protect the turbocharger from over-speeding.


Diagnosis function

The task of the diagnosis function is to detect and locate disturbances within the EMS 2 system, to protect the engine, and to provide information about problems that have developed. If a malfunction is discovered, this is announced by warning lamps, a flashing diagnostic lamp or in plain language on the instrument panel, depending on the equipment used. If a fault code is obtained as a flashing code or in plain language, this is used for guidance in any troubleshooting.

Fault codes can also be read by Volvo’s VODIA tool at authorized Volvo Penta workshops. In

case of serious malfunctions, the engine is shut down completely, or the control unit reduces the power output (depending on application). A fault code is set as a guide when fault tracing.


In- and out signals

Information from the sensors provides accurate information regarding operational conditions and makes it possible for the control unit processor to calculate the correct injection amount, injection timing and engine condition, among many other things. 

Input signals

The control unit receives input signals regarding engine operational conditions along with information from the following components:

- Coolant temperature sensor

- Charge air pressure/charge air temperature sensors

- Crankcase pressure sensor

- Position sensor

- Camshaft

- Engine speed sensor

- Flywheel

- Piston cooling pressure sensor

- Coolant level sensor

- Oil pressure sensor

- Oil level and oil temperature sensors

- Fuel pressure sensor

- Water-in-fuel sensor

- Air filter pressure sensor

- Air temperature sensor

- Fan speed

Output signals

The control unit uses the input signals to control the following components:

- Unit injector

- Start motor

- Alternator

- Main relay

- Preheat relay

- Internal EGR (TAD1350-1355GE only)

- Waste gate

- Electronic fan control




DCU (Display Control Unit)

DCU is a digital instrument panel that communicates with the engine control unit via the CAN-link. DCU has several functions, such as: Engine control

- Start, stop, rpm regulation, preheating, etc.


- Shows engine speed, charge pressure, charge temperature, coolant temperature, oil pressure, oil temperature, engine hours, battery voltage, instantaneous fuel consumption and fuel consumption (trip fuel).


- Shows fault codes in text. Lists previous faults. Parameter setting

- Idle speed, alarm limits for oil temperature/coolant temperature, regulation mode (speed droop/isochronous).

DU (Display Unit)

DU is an instrument for showing the engines operating values. The values are shown graphically on an LCD display. The display communicates via the CAN link and consists of a computerized unit for attachment to the control panel. It is connected to the CAN link between the engine control unit and CIU or DCU.


Electrical interface


This document describes how the Volvo Penta industrial engines equipped with the control systems EMS and EMS2 may be controlled. There are a number of interfaces available to control

the engine. The interfaces are:

• Bus interface



The common thing about the three first interfaces is that the engine is controlled over two serial communication buses. The CIU and DCU uses the bus interface to communicate with the engine.


If non Volvo Penta equipment is connected to the communication busses there is always a risk that the safety of the system is jeopardized.



BAM Broadcast Announce Message CAN Controller Area Network

DEF Diesel Emission Fluid

EATS Engine After Treatment System

EIC Engine Interface Connector

EECU Engine Electronic Control Unit

EMS Engine Management System

EMS 2 EMS used on TAD734GE, D9,

TAD125xVE, D13 and D16 engines

FMI Failure Mode Identifier

OEM Original Equipment Manufacturer

SPN Suspect Parameter Number

VP Volvo Penta

Relevant dokumentation

• 7748665

Electrical interface specification industrial engines

EMS and EMS2

• SAE J1939-73

• SAE J1939-71


Engine control interface

Volvo Penta industrial engines can be controlled in three different ways. Via bus interface, CIU or DCU. The bus interface is used by those who makes there own control system that and wants to control the engine over SAE J1939 and J1587. Volvo Penta provided two different systems to control the engines, CIU that provides a number of digital/analogue outputs to control the engine. And DCU that has all buttons included in the unit but still provides some digital/analogue inputs and outputs. 



This is the interface for those who wants to make there control panel or non bus based control unit. 



This is the interface for those who wants a complete

unit that is ready to run the engine without make any button. But the possibility to make some customization is still here. The DCU is equipped with a display that shows engine data and diagnostics translated to text.


Electrical interface

Bus interface

8-pole deutsch connector recepticle.

Pin Description



3 Battery –

4 Battery +

5 Ignition and stop request if energized to run

6 Stop request energized to stop

7 J1587A

8 J1587B



The electrical interface to the CIU is 42-pole AMP connector.


Pin Description Pin Description

1 Idle request 22 J1587A

2 Potentiometer ground 23 Not used

3 Potentiometer signal 24 Preheat indication(1)

4 Not used 25 Coolant level alarm

5 Not used 26 Oil pressure alarm

6 Not used 27 Battery +

7 Over speed indication(2)

Buzzer (3)

28 Ignition (key switch)

8 Easy link bus 29 Governor mode request

9 Coolant temperature alarm 30 Potentiometer supply

10 Battery alarm 31 Not used

11 CAN L 32 Not used

12 CAN H 33 Tachometer

13 Gauge power supply 34 Coolant temperature gauge

14 Battery – 35 Start request

15 Frequency select(4) 36 Diagnostic indication

16 Diagnostic switch 37 J1587B

17 Preheat request(5) 38 Running indication(6)

18 Not used 39 Fuel alarm

19 Engine protection override req. 40 Oil temperature alarm

20 Oil temp gauge 41 Stop request

21 Oil pressure gauge 42 Not used



There is a cable harness available with all wires connected that applies to the above table.

All indicators shall be less than 3W. All switches are active when shorted to battery+.


Connector 1, 8-pole deutsch connector.


Pin Description Pin Description

1 CAN H 5 Ignition and stop request if energized to


2 CAN L 6 Stop request energized to stop

3 Battery – 7 J1587A

4 Battery + 8 J1587B


Connector 2, 12-pole deutsch connector:

Pin Description Pin Description

1 External stop 7 Throttle + (10V)

2 External Start / Ignition 8 Throttle input

3 LSS1 (Buzzer) 9 Throttle –

4 Easylink gauge power 10 LSS2 (Running indication)

5 Easylink Data 11 LSS3 (spare)

6 Easylink Ground


All indicators shall be less than 3W. All switches are active when shorted to battery +.


Power up sequence

The system powers up when the ignition is switched



A start request is addressed by the start signal. The engine will then start to crank and it will continue to do so until one of the following conditions becomes true.

• The start signal goes inactive.

• The engine speed exceeds a stated limit, typical about 480 rpm.

• The cranking time exceeds a stated limit, typical about 20 s. 30 s for genset engines.

Bus interface

Associated message:

J1939: Start request in VP Status

J1587: Start request in PPID 98


Associated hardware/input:

Start request.


Associated hardware/input:

Start request.

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