Electronic Control Module



The tractor engine equipped by Electronic Control Module (ECM) (1) with functions as a governor and a computer for the fuel system. The ECM receives signals from the sensors in order to control the timing and the engine speed. The electronic system consists of the Electronic Control Module (ECM), the engine sensors and inputs from the parent machine. The ECM is the computer. The personality module is the software for the computer. The personality module contains the operating maps. The operating maps define the following characteristics of the engine:
• Engine power
• Torque curves
• Engine speed (rpm)
• Engine Noise
• Smoke and Emissions
The factory passwords restrict changes to authorized personnel. Factory passwords are required to clear any event code. The Electronic Control Module (ECM) has an excellent record of reliability. Any problems in the system are most likely to be the connectors and the wiring harness. The ECM should be the last item in troubleshooting the engine. The personality module contains the software with all the fuel setting information. The information determines the engine performance. The personality module is installed behind the access panel on the ECM. Flash programming is the method of programming or updating the personality module.

Engine Speed Governor

The electronic controls determine the injection timing, the amount of fuel that is delivered to the cylinders and the intake manifold pressure if an electronically controlled wastegate is installed on the turbocharger. These decisions are based on the actual conditions and the desired conditions at any given time. The governor has software that compares the desired engine speed to the actual engine speed. The actual engine speed is determined through the primary speed/timing sensor and the secondary speed/timing sensor. If the desired engine speed is greater than the actual engine speed, the governor injects more fuel in order to increase engine speed.

Timing Considerations

Once the governor has determined the amount of fuel that is required, the software must determine the timing of the fuel injection. Fuel injection timing is determined by the ECM after considering input from the following components:
• Engine coolant temperature sensor
• The sensor for the intake manifold air temperature
• The sensor for the intake manifold pressure
At start-up, the ECM determines the top center position of the number 1 cylinder from the secondary speed/timing sensor in the fuel injection pump. The Electronic Control Module (ECM) decides when fuel injection should occur relative to the top center position. The ECM optimizes engine performance by control of each of the electronic unit injectors so that the required amount of fuel is injected at the precise point of the engine’s cycle. The electronic unit injectors are supplied high pressure fuel from the fuel injection pump. The ECM also provides the signal to the solenoid in the fuel injection pump. The solenoid in the fuel injection pump controls a valve in the fuel injection pump. This valve controls the pressure in the fuel injection pump. Fuel that is not required for the engine is diverted away from the fuel injection pump back to the fuel tank. The ECM adjusts injection timing and fuel pressure for the best engine performance, the best fuel economy and the best control of exhaust emissions. The actual timing can be viewed with an electronic service tool. Also, the desired timing can be viewed with an electronic service tool.

Fuel Injection

The personality module inside the ECM sets certain limits on the amount of fuel that can be injected. The FRC Limit is a limit that is based on intake manifold air pressure and engine rpm. The FRC Limit is used to control the air/fuel ratio in order to control the engine’s exhaust emissions. When the ECM senses a higher intake manifold air pressure, the ECM increases the FRC Limit. A higher intake manifold air pressure indicates that there is more air in the cylinder. When the ECM increases the FRC Limit, the ECM allows more fuel into the cylinder. The Rated Fuel Limit is a limit that is based on the power rating of the engine and on the engine rpm.
The Rated Fuel Limit enables the engine power and torque outputs to conform to the power and torque curves of a specific engine model. These limits are in the personality module and these limits cannot be changed.

Speed/Timing Sensor

Timing wheel on the crankshaft

The primary engine position is a passive sensor. The timing wheel is located on the crankshaft. The speed/timing sensor receives a signal from the teeth on timing wheel. The extra space on the timing wheel gives one revolution per space. The space is oriented so that the space is 40 degrees after top center.

Schematic for speed/timing sensor

When the engine is cranking, the ECM uses the signal from the speed/timing sensor in the fuel injection pump. When the engine is running the ECM uses the signal from the speed/timing sensor on the crankshaft. This speed/timing sensor is the primary source of the engine position.

Pressure Sensors

Schematic for pressure sensors

The boost pressure sensor and the engine oil pressure sensor are active sensors. The boost pressure sensor provides the ECM with a measurement of inlet manifold pressure in order to control the air/fuel ratio. This will reduce the engine smoke during transient conditions. The operating range of the boost pressure sensors:
For standard power engines, the range is up to the following........ 339 kPa (49.169 psi).
For all high power engine, the range is up to the following............ 440 kPa (63.818 psi).
The engine oil pressure sensor provides the ECM with a measurement of engine oil pressure. The ECM can warn the operator of possible conditions that can damage the engine. This includes the detection of an oil filter that is blocked.
The operating range for the engine oil pressure sensor........ 55 kPa to 339 kPa (8 psi to 50 psi).

Temperature Sensors

Schematic for the temperature sensors

The air inlet temperature sensor and the coolant temperature sensor are passive sensors. Each sensor provides a temperature input to the ECM. The ECM controls following operations:
• Fuel delivery
• Injection timing
The operating range for the sensors..... 40 °C to 150 °C (��40 °F to 302 °F)
The sensors are also used for engine monitoring.

Power Sources

Power Supplies
The 6 cylinder Tractor Engine supplies power to the ECM. The ECM powers the following components:
• All sensors on the engine
• The solenoid for the fuel Injection Pump
• The solenoid for the Waste gate (optional)
• Diagnostic connector
• Electronic unit injectors
The glow plugs are powered directly from the battery

ECM Power Supply 

Schematic for ECM

The power supply to the ECM and the system is drawn from the 24 volt or the 12 volt battery. The power supply for the ECM has the following components:
• Battery
• disconnect switch
• Key start switch
• Fuses
• Ground bolt
• ECM connector
• Machine interface connector
The Schematic for the ECM shows the main components for a typical power supply circuit. Battery voltage is normally connected to the ECM. The input from the key start switch turns on the ECM. The wiring harness can be bypassed for troubleshooting purposes. The display screen on the electronic service tool can be used in order to check the voltage supply.

Power Supply for the Pressure Sensors

Schematic for pressure sensors

The ECM supplies 5.0 ± 0.2 DC volts through the ECM connector to each sensor. The power supply is protected against short circuits. A short in a sensor or a wiring harness will not cause damage to the ECM.

Power supply for the Glow plugs

Schematic for the glow plugs