Discovery 2. Manual - part 465

ENGINE MANAGEMENT SYSTEM - TD5

DESCRIPTION AND OPERATION

18-1-3

Engine management component 
location - engine compartment

LHD illustrated

1 Ambient air pressure sensor
2 Engine coolant temperature sensor
3 Glow plugs
4 Engine Control Module (ECM)
5 Fuel pump relay
6 Main relay
7 A/C clutch and cooling fan relays
8 Manifold absolute pressure/ inlet air 

temperature sensor

9 Electronic vacuum regulator solenoid

10 Fuel temperature sensor
11 Crankshaft speed and position sensor
12 Electronic unit injectors
13 Turbocharger wastegate modulator
14 Mass air flow sensor 
15 Clutch switch

ENGINE MANAGEMENT SYSTEM - TD5

18-1-4

DESCRIPTION AND OPERATION

Engine management block diagram

ENGINE MANAGEMENT SYSTEM - TD5

DESCRIPTION AND OPERATION

18-1-5

1 Mass air flow sensor 
2 Ambient air pressure sensor
3 Manifold absolute pressure/ inlet air 

temperature sensor

4 Engine coolant temperature sensor
5 Crankshaft speed and position sensor
6 Throttle position sensor
7 Fuel temperature sensor
8 Brake pedal switch
9 Clutch switch 

10 High/ Low ratio switch 
11 Main relay
12 Malfunction indicator lamp
13 Fuel pump relay
14 Glow plug warning lamp
15 Glow plugs

16 Electronic unit injectors
17 Turbocharger wastegate modulator
18 EGR modulator
19 Diagnostic connector
20 Engine control module
21 Cruise control master switch
22 Cruise control SET+ switch
23 Cruise control RES switch
24 Air conditioning clutch relay 
25 Air conditioning cooling fan relay
26 Electronic automatic transmission ECU
27 Self levelling and anti-lock brakes ECU
28 Instrument cluster
29 Body control unit

ENGINE MANAGEMENT SYSTEM - TD5

18-1-6

DESCRIPTION AND OPERATION

Description

General
An engine control module (ECM) controls the five-cylinder direct injection diesel engine, and works on the drive by 
wire principle. This means there is no throttle cable, the ECM controls the drivers needs via a signal from the Throttle 
Position (TP) sensor on the throttle pedal.

The ECM is a full authoritative diesel specific microprocessor that also incorporates features for cruise control and air 
conditioning control. In addition, the ECM supplies output control for the exhaust gas recirculation and turbocharger 
boost pressure. The ECM has a self-diagnostic function, which is able to provide backup strategies for most sensor 
failures.

The ECM processes information from the following input sources:

l

Mass air flow sensor. 

l

Ambient air pressure sensor. 

l

Manifold absolute pressure/inlet air temperature sensor. 

l

Engine coolant temperature sensor. 

l

Crankshaft speed and position sensor. 

l

Throttle position sensor.

l

Fuel temperature sensor. 

l

Air conditioning request.

l

Air conditioning fan request.

l

Brake pedal switch. 

l

Clutch switch. 

l

Cruise control master switch.

l

Cruise control SET+ switch.

l

Cruise control RES switch.

l

High/low ratio switch.

The input from the sensors constantly updates the ECM with the current operating condition of the engine. Once the 
ECM has compared current information with stored information within its memory, it can make any adjustment it 
requires to the operation of the engine via the following: 

l

Air conditioning clutch relay. 

l

Air conditioning cooling fan relay. 

l

Electronic vacuum regulator solenoid.

l

Malfunction indicator lamp.

l

Fuel pump relay. 

l

Glow plug warning lamp.

l

Glow plugs. 

l

Fuel injectors.

l

Main relay.

l

Turbocharger wastegate modulator.

l

Temperature gauge.

The ECM interfaces with the following:

l

Electronic Automatic Transmission (EAT).

l

Self Levelling and Anti-lock Brakes System (SLABS).

l

Serial communication link.

l

Instrument cluster.

l

Body Control Unit (BCU).