Engine Control Module (ECM) 4.0L (Discovery 3)

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

Incoming Signals

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

• Central switching unit
• Coolant temperature
• brake switch
• Manifold absolute pressure
• Accelerator pedal position 1
• Accelerator pedal position 2
• Throttle position 1
• Throttle position 2
• Engine cooling system fan speed
• Position and engine speed sensor (crankshaft sensor)
• Camshaft position sensor
• Engine oil temperature
• IAT sensor (intake air temperature) (built into MAF (mass air flow))
• MAF (mass air flow)
• knock sensors (2)
• Cruise Control Speed Switches (resistive ladder chains)
• oxygen sensors (4)
• Vehicle speed (via CAN bus (local area network of controllers))
• Differential pressure eGr (exhaust gas recirculation)
• EGR (exhaust gas recirculation) mAp (manifold absolute pressure)
• Generator control circuits

Output signals

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

• Throttle actuator
• Ignition coils (6)
• Oxygen sensor heaters (4)
• fuel injectors (6)
• EGR valve (exhaust gas recirculation)
• IMT valve (intake manifold adjustment)
• Purge valve
• Fuel pump relay
• Starter relay
• A/C Condenser Fan Module (CAN (local area network of controllers))
• EMS Power Relay
• Control of the viscous coupling of the fan of the cooling system
• Generator control

ECM block (the engine control unit) controls the phased fuel supply to all engine cylinders. The engine uses an ignition system with separate ignition coils (6 coils), which are installed directly on the spark plugs. To maintain optimum engine performance, the ECM (the engine control unit) detects knocking in each individual cylinder and suppresses it by adjusting the ignition timing in each cylinder.

ECM Management Strategy (the engine control unit) is based on the amount of torque requested by the driver and various vehicle ECUs. The EMS uses various sensors to determine the amount of torque that an engine needs to produce. These include:

• Mass air flow sensor
• Accelerator pedal position sensor
• Engine temperature sensors
• oxygen sensors

The EMS processes these signals and decides on the amount of torque to be generated. Torque is generated by various actuators supplying air, fuel and ignition sparks to the engine (electronic throttle valve, injectors, coils, etc.). EMS also via CAN bus (local area network of controllers) communicates with other vehicle ECUs to obtain additional data. These include:

• ABS control unit (anti-lock braking system)
• TCM (transmission control unit)
• Transfer box controller

contact no	Purpose	Input signal / output signal
1	CAN (local area network of controllers)	Input signal / output signal
2	CAN (local area network of controllers)	Input signal / output signal
3	Determining the state of the generator	Input signal
4	Weight UHEGO row A	-
5	Weight UHEGO series B	-
6	- engine start sensor	Input signal
7	Camshaft sensor weight	-
8	Not used	-
9	Not used	-
10	Sensor weight 3	-
11	Sensor weight 4	-
12	Sensor weight 5	-
13	Not used	-
14	Reserve weight	-
15	Sensor weight 6	-
16	Not used	-
17	Not used	-
18	Mass MAF (mass air flow)	-
19	Bank A knock sensor ground	-
20	Bank B knock sensor ground	-
21	Not used	-
22	Not used	-
23	Oil temperature sensor	Input signal
24	Sensor power supply 6	Output signal
25	LIN A	Output signal
26	UHEGO Series B (+)	Input signal
27	UHEGO Series B (-)	-
28	UHEGO series A (+)	+
29	UHEGO series A (-)	-
30	+ engine start sensor	Input signal
31	Not used	-
32	Not used	-
33	Not used	-
34	CMP sensor signal (camshaft position) row A	Input signal
35	Not used	-
36	Not used	-
37	Not used	-
38	Differential pressure sensor	Input signal
39	Not used	-
40	Fuel pressure sensor	Input signal
41	Not used	-
42	Bank A knock sensor (+)	Input signal
43	Bank B knock sensor (+)	Input signal
44	Not used	-
45	Not used	-
46	Fuel temperature sensor	Input signal
47	Sensor power supply 5	Output signal
48	Sensor power supply 4	Output signal
49	Not used	-
50	Not used	-
51	Not used	-
52	Not used	-
53	Not used	-
54	Not used	-
55	Not used	-
56	Cylinder 3 B ignition coil	Output signal
57	Cylinder coil 3 A	Output signal
58	Cylinder 2 B ignition coil	Output signal
59	Ignition coil cylinder 2 A	Output signal
60	Ignition coil cylinder 1 B	Output signal
61	Cylinder coil 1 A	Output signal
62	Bank A ignition coil weight	-
63	Viscous fan control circuit	Input signal
64	Bank B ignition coil weight	-
65	Throttle position sensor 1	-I
66	Air temperature sensor	Input signal
67	Throttle position sensor 2	Input signal
68	coolant temperature sensor	Input signal
69	MAP (manifold absolute pressure)	Input signal
70	MAF (mass air flow)	Input signal
71	Not used	-
72	Sensor power supply 3	Output signal
73	Not used	-
74	throttle direction (-)	Output signal
75	throttle direction (+)	Output signal
76	UHEGO heater row A	Output signal
77	Row B UHEGO heater	Output signal
78	Nozzle cylinder 1 B	Output signal
79	Nozzle cylinder 1 B	Output signal
80	Nozzle cylinder 2 A	Output signal
81	Nozzle cylinder 2 B	Output signal
82	Cylinder nozzle 3 A	Output signal
83	Nozzle cylinder 3 B	Output signal
84	Intake manifold control valve 1	Output signal
85	Not used	-
86	Not used	Output signal
87	Not used	Output signal
88	Not used	Output signal
89	Not used	-
90	EGR (exhaust gas recirculation)	Input signal
91	Not used	-
92	Purge valve	Output signal
93	Cooling fan viscous clutch adjustment request	Output signal
94	Not used	-
95	Fuel pump relay	Output signal
96	Generator control	Output signal

C0635 ECM Connector Pin Chart

contact no	Purpose	Input signal / output signal
1	Signal mass 1	-
2	Force Mass 1	-
3	Force Mass 2	-
4	ECM Power (the engine control unit)	Input signal
5	Force Mass 3	-
6	APP sensor weight (accelerator pedal position) 1	-
7	APP sensor weight (accelerator pedal position) 2	-
8	Not used	-
9	Not used	-
10	Not used	-
11	Not used	-
12	Park/neutral position signal	Input signal
13	Not used	-
14	Not used	-
15	Not used	-
16	EMS relay	Output signal
17	crankshaft request	Output signal
18	+ CAN bus (local area network of controllers)	Output signal
19	Sensor power 2 APP (accelerator pedal position)	Output signal
20	Fuel pump control	Output signal
21	Not used	-
22	Not used	-
23	Not used	-
24	APP sensor signal (accelerator pedal position) 1	Output signal
25
26	Stoplight switch	Input signal
27	Not used	-
28	Not used	-
29	Not used	-
30	ignition switch	Input signal
31	+ CAN bus (local area network of controllers)	Input signal
32	Sensor Power 1 APP (accelerator pedal position)	Output signal
33	DMTL	Output signal
34	Not used	-
35	- speed switch	Output signal

Electronic Throttle

The V6 engine's torque is controlled in the throttle body, which is located on the intake manifold in the engine bay. APP sensor (accelerator pedal position) registers the driver's command to change the throttle position. This signal is input to the ECM and the throttle valve is opened by a motor built into the throttle body to change the angle. A sensor in the throttle body determines the position of the throttle and the rate of change of its angle of rotation. ECM Software (the engine control unit) provides for the calibration of the damper position in each ignition cycle. When the ignition is turned on (ON position), ECM (the engine control unit) fully opens and closes the throttle, thereby performing self-diagnosis and calibration. Throttle body to attenuate electrical noise connected to ECM (the engine control unit) with a pair of twisted wires. For more information refer to Acceleration Control (310-02A)

Throttle connector pin chart C0175

contact no	Purpose	Input signal / output signal
1	Signal 1	Output signal
2	Power supply 5 V	Input signal
3	Signal 2	Output signal
4	Weight	-
5	+ drive	Input signal
6	- drive	-