After Market Device - An after market device is a device or an accessory that is installed by the customer after the vehicle is delivered.
Air-To-Air Aftercooler - An air-to-air aftercooler is a device that is used on turbocharged engines in order to cool inlet air that has undergone compression. The inlet air is cooled after the inlet air passes through the turbocharger. The inlet air is passed through an aftercooler (heat exchanger) that uses ambient air for cooling. The inlet air that has been cooled advances to the inlet manifold.
Alternating Current (AC) - The direction of the current flow changes. The current flow alternates constantly.
American Wire Gauge (AWG) - AWG is a measure of the diameter of electrical wire. AWG is also a measure of the current carrying capacity of electrical wire. When the AWG number is smaller, the diameter of the wire is larger. When the AWG number is larger, the diameter of the wire is smaller.
Atmospheric Pressure Sensor - The atmospheric pressure sensor measures barometric pressure. The sensor sends a signal to the electronic control module (ECM). The signal is used in engine control and in engine operation.
Before Top Center (BTC) - BTC is the 180 degrees of crankshaft rotation before the piston reaches the top center position in the normal direction of rotation.
Boost Pressure Sensor - The boost pressure sensor measures inlet manifold air pressure. The boost pressure sensor sends a signal to the Electronic Control Module (ECM).
Bypass Circuit - A bypass circuit is a circuit that is used as a substitute circuit for an existing circuit. A bypass circuit is typically used as a test circuit.
Calibration - Calibration is an electronic adjustment of a sensor signal.
CAT Data Link - The data link is an electrical connection that is used to communicate with other devices that utilize microprocessors. The microprocessor based devices are compatible with the proposed American Trucking Association and the SAE standard. These devices include trip recorders, electronic dashboards, and maintenance systems. The data link is also the communication medium that is used for programming with the electronic service tool. The data link is also used for troubleshooting with the electronic service tool.
Caterpillar Engine Monitoring - The part of the Caterpillar Electronic Engine Control that monitors coolant temperature, oil pressure, inlet manifold air temperature, and coolant level. Caterpillar engine monitoring then informs the operator of any problems that are detected. The Coolant Temperature, Inlet Manifold Air Temperature, and Oil pressure Sensors are supplied by Caterpillar and Monitored by the ECM. The coolant level sensor is installed by the OEM factory but still monitored by the ECM. This is opposed to an aftermarket Engine Monitoring System. An aftermarket Engine Monitoring System does not interface with the Caterpillar Electronic Engine Control.
Clutch Switch - The clutch switch is supplied by the OEM factory. The clutch switch is a limit switch. The usually adjustable switch is mounted near the pedal. When the pedal is released, the switch is closed. Depressing the clutch will open the circuit.
Code - See the Diagnostic Code.
Coolant Level Sensor - The sensor detects the absence of coolant at the probe. The sensor also detects the presence of coolant at the probe. The sensor then sends the appropriate signal to the ECM.
Coolant Temperature Sensor - The coolant temperature sensor measures the engine coolant temperature. The sensor sends a signal to the electronic control module (ECM). The engine's coolant temperature is used in Cold Mode operation. Coolant temperature is also used in order to optimize engine performance.
Custom Data - The custom data is for monitoring purposes. The ECM stored trip data holds the custom data. The custom data allows the owner to specify operating parameters of the engine application.
Customer Specified Parameters - A customer specified parameter is a parameter that can be changed. A customer specified parameter's value is set by the customer. These parameters are protected by customer passwords.
Dash Check Engine Lamp - The dash check engine lamp is sometimes called the diagnostic lamp. The dash check engine lamp is used to warn the operator of the presence of an active diagnostic code.
Desired RPM - The desired rpm is input to the electronic governor within the ECM. The electronic governor uses the signal from the Accelerator Pedal Position Sensor, the Engine Speed Sensor, the Cruise Control, and the Customer Parameters in order to determine desired rpm.
Diagnostic Code - A diagnostic code is sometimes called a fault code. A diagnostic code is an indication of a problem or event in the electrical engine systems.
Diagnostic Event Code - These codes indicate an event. Diagnostic event codes are not necessarily an indication of problem within the electronic system.
Diagnostic Fault Code - Diagnostic fault codes indicate an electronic system malfunction that indicates a problem with the electronic system.
Diagnostic Flash Code - Diagnostic flash codes are used to indicate a malfunction within the electronic system. Diagnostic flash codes are also used to indicate an event that is detected by the electronic system. The codes are flashed on the dash check engine lamp.
Diagnostic Lamp - A diagnostic lamp is sometimes called the check engine light. The diagnostic lamp is used to warn the operator of the presence of an active diagnostic code.
Direct Current (DC) - Direct current is the type of current that flows consistently in only one direction.
Dual Coil Speed Sensor - The movement of the teeth on the output shaft of the transmission is detected by the dual coil speed sensor. The sensor contains two coils. One coil is used to supply a signal to the speedometer. The second coil is used to supply a signal to the speed buffer.
Duty Cycle - See Pulse Width Modulation.
Electronic Control Analyzer Programmer (ECAP) - The ECAP is a Caterpillar electronic service tool. The ECAP is used for programming and for diagnosing various types of electronic controls.
Electronic Control Module (ECM) - The ECM is the engine's control computer. The ECM provides power to the electronics. The ECM monitors data that is input from the engine's sensors. The ECM acts as a governor in order to control engine rpm.
Electronic Unit Injector - The fuel injection pump and the fuel injector nozzle assembled. The amount of fuel that is injected is controlled by the electronics. The pumping action is controlled mechanically.
ECM Fan Control - The ECM controls the cooling fan relay. The ECM uses the following information to control the cooling fan relay: coolant temperature and the high pressure switch on the air conditioner.
Electronic Engine Control - The electronic engine control is a complete electronic system. The electronic engine control monitors the engine operation under all conditions. The electronic engine control also controls the engine operation under all conditions.
Electronic Technician (ET) - The ET is a Caterpillar electronic service tool that is used for diagnosing and programming a variety of electronic controls.
Engine Speed/Timing Sensor - The engine speed/timing sensor provides a pulse width modulated signal to the ECM. The ECM interprets the signal as the crankshaft position and the engine speed.
Failure Mode Identifier (FMI) - The FMI describes the type of failure that was experienced by the component. The codes for the FMI were adopted from the standard practices of SAE (J1587 diagnostics).
Flash Code - TheCaterpillar code numbers that are displayed on the diagnostic lamp.
Fuel Ratio Control (FRC) - The FRC is a limit that is based on the control of the fuel to air ratio. The FRC is used for emission control. When the ECM senses a higher turbocharger outlet pressure, the ECM increases the limit for the FRC in order to allow more fuel into the cylinders.
Fuel Position - The fuel position is a signal within the ECM. The signal is from the electronic governor. The signal goes to the fuel injection control. The signal is based on the desired engine speed, the FRC, the rated position, and the actual engine speed.
Fuel Temperature Sensor - This sensor detects the fuel temperature. The ECM monitors the fuel temperature. The ECM then calculates the needed fuel rate.
Full Load Setting (FLS) - The full load setting is used to fine tune the fuel system at the factory. The correct value for the parameter is printed on the 115-5852 Plates and Films. The parameter must be programmed. The diagnostic code 253-02 Customer or System Parameters will be displayed.
Full Torque Setting (FTS) - Full torque setting is similar to Full Load Setting. The parameter must be programmed. The diagnostic code 253-02 Customer or System Parameters will be displayed.
Harness - The harness is the bundle of wiring that connects all the components of the electrical engine system.
Hertz (Hz) - Hz is the measure of frequency in cycles per second.
Histogram - A histogram is a bar graph that indicates the relative frequency of the engine operation in specific operating ranges.
Integrated Electronic Controls - The engine is designed with the electronic controls as a necessary part of the system. The engine will not operate without the electronic controls.
Inlet Manifold Temperature Sensor - The inlet air temperature sensor is a sensor that measures the inlet air temperature. The sensor also sends a signal to the electronic control module (ECM).
Oil Pressure Sensor - The oil pressure sensor measures engine oil pressure and the oil pressure sensor sends a signal to the ECM as part of Caterpillar Engine Monitoring.
Open Circuit - An open circuit is a broken electrical wire connection. The signal or the supply voltage cannot reach the intended destination.
Parameter - A parameter is a programmable value which affects the characteristics or the behavior of the engine and/or vehicle.
Parameter Identifier (PID) - A PID is a numerical code that contains two digits or three digits. A numerical code is assigned to each component. The numerical code identifies data via the data link to the ECM.
Passive Magnetic Speed Sensor - This is a speed sensor that does not require a power and a ground connection. The sensor produces a signal that is based on the change in magnetic flux. The magnetic flux comes from a ferrous metal gear near the sensing tip.
Password - A password is a group of numeric characters or alphanumeric characters. A password is designed to restrict the changing of information in the ECM. The electrical engine systems require correct customer passwords in order to change customer specified parameters. The electrical engine systems require correct factory passwords in order to clear certain logged events. Factory passwords are also required in order to change certain engine specifications.
Personality Module - The personality module is the module in the ECM which contains all the instructions (software) for the ECM and performance maps for a specific horsepower family. Updates and rerates are accomplished by electronically flashing in new data. The updates and rerates are flashed in using an electronic service tool.
Pro-Link - The Pro-Link is an electronic service tool that is manufactured by Micro Processor Systems, Inc. (MPSI). The Pro-Link is available with a Caterpillar cartridge in order to service the Caterpillar electronic engines.
Pulse Width Modulation (PWM) - A PWM is a digital type of electronic signal that corresponds to a measured variable. The length of the pulse (signal) is controlled by the measured variable. The variable is quantified by a certain ratio. This ratio is the percent of "on-time" that is divided by the percent of "off-time". A PWM signal is generated by the Throttle Position Sensor.
Rated Fuel Position ("Rated Fuel Pos" on ECAP) - The rated fuel position indicates the maximum allowable fuel position (longest injection pulse). The rated fuel position will produce rated power for this engine configuration.
Reference Voltage - The reference voltage is a regulated voltage that is used by the sensor in order to generate a signal voltage.
Sensor - A sensor is used to detect a change in the pressure, in the temperature, or in mechanical movement. When any of these changes are detected, a sensor converts the change into an electrical signal.
Service Program Module (SPM) - The SPM is a software program on a computer chip that was programmed at the factory. The computer chip is designed to adapt an ECAP for a particular application.
Short Circuit - A short circuit is an electrical circuit that is mistakenly connected to an undesirable point. For example, an electrical contact is made with the frame whenever an exposed wire rubs against a vehicle's frame.
Signal - A signal is a voltage or a wave that is used to transmit information that is typically from a sensor to the ECM.
Speed Burp - A speed burp is a sudden brief change in engine rpm.
Speed Circuit - The speed circuit includes the speed sensor, the harness and the ECM.
Speed Sensor - The speed sensor is an electromagnetic pickup that measures speed from the rotation of gear teeth in the drive train.
Standard SAE Diagnostic Communications Data Link - For more information, refer to ATA Data Link.
Subsystem - A subsystem is a part of the engine system that relates to a particular function.
Supply Voltage - Supply voltage is a constant voltage that is supplied to a component in order to provide electrical power for operation. Supply voltage may be generated by the ECM. Supply voltage may also be the battery voltage of the vehicle that is supplied by the vehicle wiring.
"T" Harness - This harness is a test harness that is designed to permit normal circuit operation and the measurement of the voltage simultaneously. Typically, the harness is inserted between the two ends of a connector.
Throttle Position - The throttle position is interpreted by the ECM. The accelerator pedal position sensor sends the ECM signals. The throttle position may be used as part of a power take-off control.
Throttle Position Sensor - The throttle position sensor is an electronic sensor that is connected to the throttle pedal. The throttle position sensor sends a pulse width modulated signal to the ECM.
Total Tattletale - The total tattletale is the total number of changes to all system parameters.
Transducer - A transducer is a device that converts a mechanical signal to an electrical signal.
Vehicle Speed Circuit - The vehicle speed circuit includes the vehicle speed sensor, the harness, and the ECM.
Vehicle Speed Sensor - A vehicle speed sensor is an electromagnetic pickup that measures vehicle speed from the rotation of gear teeth in the drive train of the vehicle.
Warning Lamp - The warning lamp is used to warn the operator of the presence of a Caterpillar engine monitoring detected problem.