General

ENGINE MANAGEMENT SYSTEM - SIEMENS

18-4-8

DESCRIPTION AND OPERATION

Description

General
The KV6 engine is fitted with a Siemens MS43 Engine Management System (EMS), which is an adaptive system that 
maintains engine performance at the optimum level throughout the life of the engine.

The EMS consists of an Engine Control Module (ECM) that uses inputs from engine sensors and from other vehicle 
systems to continuously monitor driver demand and the current status of the engine. From the inputs the ECM 
calculates the Air Fuel Ratio (AFR) and ignition timing required to match engine operation with driver demand, then 
outputs the necessary control signals to the electric throttle, fuel injectors and ignition coils. The ECM also outputs 
control signals to operate the:

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Air Conditioning (A/C) compressor.
 

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 AIR CONDITIONING, DESCRIPTION AND OPERATION, Description.

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Engine cooling fans.
 

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 COOLING SYSTEM - K SERIES KV6, DESCRIPTION AND OPERATION, Description.

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Evaporative emissions (EVAP) purge valve and Diagnostic Module for Tank Leakage (DMTL).
 

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 EMISSION CONTROL - K SERIES KV6, DESCRIPTION AND OPERATION, Description.

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Fuel pump.
 

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 FUEL DELIVERY SYSTEM - K SERIES KV6, DESCRIPTION AND OPERATION, Description.

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Variable Intake System (VIS).
 

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 MANIFOLD AND EXHAUST SYSTEM - K SERIES KV6, DESCRIPTION AND OPERATION, 

Description.

The ECM also interfaces with the:

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Immobilisation ECU, for re-mobilisation of the engine fuel supply.
 

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 SECURITY, DESCRIPTION AND OPERATION, Description.

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Cruise control interface ECU, to operate cruise control.
 

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 ENGINE MANAGEMENT SYSTEM - SIEMENS, DESCRIPTION AND OPERATION, Cruise Control 

Description.

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Electronic Automatic Transmission (EAT) ECU, to assist with control of the gearbox.
 

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 AUTOMATIC GEARBOX - JATCO, DESCRIPTION AND OPERATION, Description.

Sensor inputs and engine performance are monitored by the ECM, which illuminates the SERVICE ENGINE SOON 
(MIL) and/or the SERVICE ENGINE warning lamps in the instrument pack if a fault is detected.

As part of the security system's immobilisation function, a vehicle specific security code is programmed into the ECM 
and the immobilisation ECU during production. The ECM cannot function unless it is connected to an immobilisation 
ECU with the same code. In service, replacement ECM's are supplied uncoded and must be configured, using 
TestBook/T4, to learn the vehicle security code from the immobilisation ECU.

A 'flash' Electronic Erasable Programmable Read Only Memory (EEPROM) allows the ECM to be externally 
configured, using TestBook/T4, with market specific or new tune information up to 14 times. The current engine tune 
data can be accessed and read using TestBook/T4.

The ECM memorises the position of the crankshaft and the camshaft when the engine stops. During cranking on the 
subsequent start the ECM confirms their positions from sensor inputs before initiating fuel injection and ignition.

To achieve optimum performance the ECM is able to 'learn' the individual characteristics of an engine and adjust the 
fuelling calculations to suit. This capability is known as adaptive fuelling. Adaptive fuelling also allows the ECM to 
compensate for wear in engine components and to compensate for the tolerance variations of the engine sensors.

If the ECM suffers an internal failure, such as a breakdown of the processor or driver circuits, there is no back up 
system or limp home capability. If a sensor circuit fails to supply an input, where possible the ECM adopts a substitute 
or default value, which enables the engine to function, although with reduced performance in some cases.