RG10765
–UN–26MAY00
A—ECT Sensor (Rear of C—Fuel Pressure Sensor E—Pump Position Sensor H—ECT Sensor (Thermostat
Cylinder Head) D—Electronic Transfer Pump F—Crankshaft Position Sensor Housing)
B—Oil Pressure Sensor Connector G—PSG Connector I—MAT Sensor
NOTE: For information on Tier 1 vs. Tier 2 applications, see ENGINE APPLICATION CHART in Group 001 earlier in this manual. NOTE: Some of the components shown are optional
and not used on all applications.
The electronic control system sends the PSG (pump control unit) fuel delivery quantity information. In order
to achieve this, the engine control system
encompasses the following performance functions:
• Constantly monitors engine operating conditions
• Precisely determines piston position
• Informs the PSG of desired fuel quantity
• Provides multiple control modes
03 140 6
RG41221,0000112 –19–17OCT02–1/1
Electronic Control System Overview - Tier 2
RG11712
–UN–20JUN01
A—ECT Sensor (Rear of C—Fuel Pressure Sensor E—Pump Position Sensor H—ECT Sensor (Thermostat
Cylinder Head) D—Electronic Transfer Pump F—Crankshaft Position Sensor Housing)
B—Oil Pressure Sensor Connector G—PSG Connector I—MAT Sensor
NOTE: For information on Tier 1 vs. Tier 2 applications, see ENGINE APPLICATION CHART in Group 001 earlier in this manual. NOTE: Some of the components shown are optional
and not used on all applications.
The electronic control system sends the PSG (pump control unit) fuel delivery quantity information. In order
to achieve this, the engine control system
encompasses the following performance functions:
• Constantly monitors engine operating conditions
• Precisely determines piston position
• Informs the PSG of desired fuel quantity
• Provides multiple control modes
• Performs self-diagnosis
03 140 7 RG41221,0000113 –19–17OCT02–1/3
Measuring Temperature
RG11819 –UN–17AUG01Temperature Sensor Schematic The Engine Coolant Temperature (ECT) sensor and the
Manifold Air Temperature (MAT) sensor are thermistors (temperature sensitive variable resistors). The sensors’ resistance goes down as the temperature that it is exposed to goes up (negative temperature coefficient). Higher temperatures result in lower voltages and lower temperatures result in higher voltages. The Engine Control Unit (ECU) sends 5 volts to the sensor, monitors the voltage drop across the sensor, and compares the voltage drop to preprogrammed values in the ECU’s memory in order to determine temperature. In addition to temperature sensors, some applications use temperature switches. The loss of coolant temperature switch is an example. Temperature switches close when a specific temperature is reached.
03 140 8 RG41221,0000113 –19–17OCT02–2/3 RG10766 –UN–26MAY00
ECT Sensor (Rear of Cylinder Head)
RG11096
–UN–15JAN03
ECT Sensor (Thermostat Housing)
A—ECT Sensor (Rear of Cylinder Head) H—ECT Sensor (Thermostat Housing)
Engine Coolant Temperature (ECT) Sensor
The Engine Coolant Temperature (ECT) sensor is located in the rear of the cylinder head (A) or in the thermostat housing (H) depending on the application using this engine.
NOTE: On OEM applications, the ECU uses the ECT sensor in the thermostat housing. Other applications may use the sensor located in the rear of the head.
The ECU monitors coolant temperature for:
• Engine protection purposes. For more information on engine protection and derate programs see, ENGINE PROTECTION or DERATE PROGRAMS later in this Group.
• Starting fuel quantity determination — The ECU will adjust the amount of fuel delivered during start-up based on initial ECT readings.
• Idle speed determination — In order to speed engine warm-up, the ECU will increase idle speed after start-up if a low coolant temperature is measured.
Continued on next page
03 140 9 RG41221,0000113 –19–17OCT02–3/3 RG10769 –UN–15JAN03
MAT Sensor - Tier 1
RG11738A
–UN–15JAN03
MAT Sensor - Tier 2
I—MAT Sensor Intake Manifold I—MAT Sensor Crossover Tube
Manifold Air Temperature (MAT) Sensor
The Manifold Air Temperature (MAT) sensor is located in the intake manifold (I) or in the cross over tube (I). The MAT sensor measures intake air temperature to help the ECU calculate the correct fueling. The ECU also monitors manifold air temperature for engine protection purposes. For more information on engine protection and derate programs see, ENGINE PROTECTION or DERATE PROGRAMS later in this Group. This sensor is optional and is not included on all applications.
03 140 10 RG,RG34710,1533 –19–17OCT02–1/3
Measuring Pressure
RG12827 –UN–30JAN03Pressure Sensor Schematic The system’s pressure sensors are 3 wire variable
resistors. As the pressure changes, sensor resistance changes. The ECU sends a 5 volt reference voltage to the sensor, monitors the voltage returning on the sensor signal wire, and compares the voltage drop to
preprogrammed values in the ECU’s memory to determine pressure. In addition to pressure sensors, some
applications use pressure switches. Pressure switches close when a specific pressure is reached.
RG,RG34710,1533 –19–17OCT02–2/3
RG10768
–UN–15JAN03
Fuel Pressure Sensor Fuel Pressure Sensor
The fuel pressure sensor (C) is an optional sensor located in the final fuel filter housing. This sensor measures the fuel pressure on the clean side of the filter. The ECU uses the input from the sensor to control the electronic fuel transfer pump and to provide engine protection. For more information on engine protection and derate programs see, ENGINE PROTECTION or DERATE PROGRAMS later in this Group.
Continued on next page
03 140 11 RG,RG34710,1533 –19–17OCT02–3/3 RG10767 –UN–15JAN03
Oil Pressure Sensor Oil Pressure Sensor
The oil pressure sensor is an optional sensor located in the main engine galley (B). The ECU monitors oil pressure for engine protection purposes. For more information on engine protection and derate programs see, ENGINE PROTECTION or DERATE PROGRAMS later in this Group.
03 140
12 RG41221,0000029 –19–23APR03–1/9