Engine Control Module (ECM) 2.7L (Discovery 3)

ECM (the engine control unit) located in the mounting box in the chamber on the right side of the engine compartment, fixed to the bulkhead.

Mounting box

Item name	Spare part number	Description
1		Control junction box fan
2		ECM (the engine control unit)
3		Transfer box controller

Input signals

To ECM input (the engine control unit) the following signals are received:

• Coolant temperatures
• clutch switch (via parking brake controller)
• Stoplight switch (via the ABS control unit (anti-lock brakes) via CAN bus (local area network of controllers))
• Manifold absolute pressure
• Accelerator pedal positions 1
• Accelerator pedal positions 2
• Electronic throttle positions
• Viscous fan speeds
• Position and engine speed sensor (crankshaft sensor)
• Camshaft position sensor
• Engine oil temperatures
• cruise control speed switches (resistive ladder chains)
• Vehicle speeds (via CAN bus (local area network of controllers))
• Generator control circuits
• Airbag and seatbelt system module
• Manifold absolute pressure and intake air temperature

Output signals

ECM block (the engine control unit) generates output signals to control the following components and parameters:

• Throttle actuator
• nozzles (6 items)
• EGR valves (exhaust gas recirculation systems)
• Cooling fan
• Fuel pump relay
• Starter relay
• A/C Condenser Fan Module
• EMS Power Relay
• Control of the viscous coupling of the fan of the cooling system
• Generator control

To on-board network ECM (the engine control unit) connected via three connectors. In ECM (the engine control unit) contains processors and memory microchips. Actuator outputs are provided by grounding loops with ECM control circuits (the engine control unit). ECM control circuits (the engine control unit) generate heat during normal operation and dissipate it through the housing. The fan in the electronic box contributes to the cooling process by maintaining a constant temperature in the box. The fan is controlled by a thermal switch located in the mounting box. The junction box is connected to the interior of the vehicle and receives additional cooled air through the A/C system. Some sensors receive a regulated voltage supplied by the ECM (the engine control unit). This measure avoids signal distortion caused by a voltage drop when the engine is cranked by the starter.

ECM (the engine control unit) carries out self-diagnosis procedures and writes fault codes in memory. These DTCs and diagnostics can be accessed using the Land Rover approved diagnostic system. If ECM (the engine control unit) needs to be replaced, new ECM (the engine control unit) must be configured using a Land Rover approved diagnostic system as it is shipped unprogrammed. Electrically Erasable Programmable Read Only Memory EEPROM (flash memory) Allows up to 14 ECM configurations with Land Rover approved diagnostic system (the engine control unit) according to market specifics or new regulatory information. If the 15th program update is required, the ECM (the engine control unit) must be replaced. Current engine settings can be retrieved and read using the Land Rover approved diagnostic system.


When installing a new ECM (the engine control unit) it must also be synchronized with the theft deterrent control module using a Land Rover approved diagnostic system. Can't swap ECM (the engine control unit) different cars.

ECM (the engine control unit) is connected to engine sensors that allow it to control the engine's operating mode. ECM (the engine control unit) processes the sensor signals and decides what actions need to be taken to maintain optimal engine performance in terms of overall vehicle drivability, fuel efficiency and exhaust emissions. To ECM memory (the engine control unit) when programming, instructions are entered with an engine control algorithm called a control strategy. In addition, the memory contains data in the form of special tables, based on which the ECM (the engine control unit) supplies fuel and reduces exhaust emissions. By comparing information from sensors with data from ECM tables (the engine control unit) is able to form the requirements for the operation of different systems. ECM (the engine control unit) contains an adaptive strategy that updates the system when its elements undergo changes due to technological tolerances or aging.

ECM (the engine control unit) receives vehicle speed signal via CAN bus (local area network of controllers) from the ABS control module (anti-lock brakes). Vehicle speed is an important input to ECM strategies (the engine control unit). ABS control module (anti-lock brakes) determines the speed signal based on the signals from the ABS wheel speed sensors (anti-lock brakes). The frequency of these signals depends on the speed of movement. ECM (the engine control unit) uses this signal to determine the following:

• How much to reduce engine torque when shifting gears.
• When to enable speed control operation.
• To control the operation of the speed control system.
• Idling mode control on a stationary vehicle.

C0872 ECM harness connector pins

contact no	Purpose	Input signal / output signal
A1	Serial communication line with immobilizer control unit	Output signal
A2	Serial communication line with immobilizer control unit	Input signal
A3	CAN bus low signal (local area network of controllers)	Input signal / output signal
A4	CAN bus signal high (local area network of controllers)	Input signal / output signal
B1	Starter enable	Output signal
B2	APP sensor weight (accelerator pedal position)	-
B3	Mass of the temperature sensor at the outlet of the radiator	-
B4	Cruise control	Input signal
C1	APP sensor weight (accelerator pedal position) 1	-
C2	APP sensor reference voltage (accelerator pedal position) 2	Output signal
C3	ECT sensor (coolant temperature)	Output signal
C4	Cruise control	Input signal
D1	APP sensor signal (accelerator pedal position) 1	Input signal
D2	APP sensor weight (accelerator pedal position) 2	-
D3	Voltage 2	Input signal
D4	Not used	-
E1	APP sensor reference voltage (accelerator pedal position) 1	Output signal
E2	Water in fuel sensor	Input signal
E3	Brake switch 1	Input signal
E4	Inertial switch	Input signal
F1	Intake air temperature sensor	Input signal
F2	Not used	-
F3	Engine crank signal	Input signal
F4	Mass air flow sensor.	Input signal
G1	Fuel pump power control	Input signal
G2	Stoplight switch	Input signal
G3	Not used	-
G4	Not used	-
H1	Not used	-
H2	Not used	-
H3	Not used	-
H4	Not used	-
J1	Not used	-
J2	Control junction box fan	Output signal
J3	Power relay	Output signal
J4	Fuel pump relay	Output signal
K1	Not used	-
K2	Electric cooling fan control	Output signal
K3	Ignition sensor	Input signal
K4	Standby Power	Input signal
L1	Battery voltage	Input signal
L2	Battery voltage	Input signal
L3	Battery voltage	Input signal
L4	Weight	-
M1	Weight	-
M2	Weight	-
M3	Weight	-
M4	Weight	-

C0411 ECM Wiring Harness Connector Pins

contact no	Purpose	Input signal / output signal
A1	Engine oil temperature sensor	Input signal
A2	Not used	-
A3	Not used	-
A4	Not used	-
B1	Reserve analog input	Input signal
B2	Reserve analog input	Output signal
B3	CAN bus low signal (local area network of controllers)	Input signal / output signal
B4	CAN bus signal high (local area network of controllers)	Input signal / output signal
C1	Not used	Input signal
C2	Sensor weight
C3	Not used
C4	Bank B knock sensor (-)	Input signal
D1	Rail pressure sensor signal	Input signal
D2	Fuel rail pressure sensor	Output signal
D3	Bank B knock sensor (+)	Output signal
D4	Bank A knock sensor (-)	Input signal
E1	Throttle position sensor	Input signal
E2	Ground pressure sensor in the fuel rail	-
E3	Glow plug supply control, bank A	Input signal
E4	Bank A knock sensor (+)	Input signal
F1	Electronic throttle voltage	Output signal
F2	Weight of electronic throttle	-
F3	Bank B Glow Plug Monitoring	Input signal
F4	Reserved PWM output (pulse width modulation)	Output signal
G1	Active engine mount control 1	Output signal
G2	Active engine mount control 2	Output signal
G3	Glow plug relay control	Output signal
G4	Not used	-
H1	Generator command	Output signal
H2	Not used	-
H3	Not used	-
H4	Not used	-
J1	Not used	-
J2	Control junction box fan
J3	Power relay	Output signal
J4	Fuel control valve	Output signal
K1	Mass of engine oil temperature sensor	-
K2	Viscous fan control	Output signal
K3	Fuel pressure control valve	Input signal
K4	Inlet Port Shutoff Actuator	Output signal
L1	Injector command 1	Output signal
L2	Common nozzle 1	-
L3	Common nozzle 3	-
L4		Output signal
M1	Injector command 3	Output signal
M2	Injector command 5	Output signal
M3	Common injectors 5	-
M4	Weight 7	-

Connector pins C2518 ECM wiring harness

contact no	Purpose	Input signal / output signal
A1	Reserve analog input	-
A2	EGR valve position sensor (exhaust gas recirculation systems) row B	Input signal
A3	EGR valve position sensor (exhaust gas recirculation systems) row A	Input signal / output signal
A4	Not used	Input signal / output signal
B1	charge air temperature sensor	Input signal
B2	Fuel temperature sensor	Input signal
B3	Not used	-
B4	Not used	-
C1	Manifold absolute pressure sensor	Input signal
C2	Engine coolant temperature sensor	-
C3	Analog voltage 1	Input signal
C4	VGT row A	Input signal
D1	Manifold absolute pressure sensor power supply	Output signal
D2	Sensor weight M	Output signal
D3	Not used
D4	Not used
E1	Engine cooling fan monitor	Input signal
E2	Not used	-
E3	Not used	-
E4	Not used	-
F1	crankshaft position sensor	Input signal
F2	Generator Load Sensor Signal	Input signal
F3	Not used	-
F4	Not used	-
G1	Crankshaft Position Sensor Power	Output signal
G2	Mass of the crankshaft position sensor	-
G3	Variable geometry turbine drive weight	-
G4	Camshaft sensor signal	Input signal
H1	EGR (exhaust gas recirculation systems) row A (+)	Output signal
H2	EGR (exhaust gas recirculation systems) row A (-)	-
H3	Weight of camshaft position sensor	-
H4	Camshaft Position Sensor Power	Output signal
J1	EGR (exhaust gas recirculation systems) row B (+)	Output signal
J2	VGT row A (+)	Output signal
J3	Not used	Output signal
J4	Throttle actuator (+)	Output signal
K1	EGR (exhaust gas recirculation systems) row B (-)	-
K2	VGT (-)	-
K3	Not used	Input signal
K4	Throttle actuator (-)	-
L1	Not used	-
L2	Common injectors 2	-
L3	Common injectors 0	-
L4	Common injectors 4	-
M1	Power circuit ground	-
M2	Injector command 2	Output signal
M3	Injector command 0	Output signal
M4	Nozzle command 4	Output signal

Unauthorized start blocking

The IMMOBILIZER control unit receives data from the relevant vehicle systems and transmits a coded signal to the ECM (the engine control unit) to allow the engine to start if all the conditions for doing so are met. Data is decoded by ECM (the engine control unit), and if they are true, the engine starts.

The data is a continuously changing code, so the immobilizer control unit and ECM (the engine control unit) must be synchronized in case of replacement of any of the devices.

In addition, ECM (the engine control unit) protects the starter from accidental operation. The IMMOBILIZER control unit receives the engine speed signal from the ECM through the instrument cluster (the engine control unit). If the engine speed exceeds the preset value, the immobilizer control unit disables the starter operation by means of the built-in starter blocking relay. For more information refer to AntiTheft - Passive (419-01B Anti-Theft - Passive)