3126B MARINE ENGINE Caterpillar

Glossary Of Terms

Usage:

Active Diagnostic Code: Describes a condition that is currently present. Alerts the operator or service technician that an abnormal parameter for engine operation currently exists.
After Market Device: A device or accessory installed by the customer or OEM after the engine is delivered by Caterpillar.
Air-To-Air Aftercooler (ATAAC): A method of using ambient air for cooling the inlet air after the turbocharger. The inlet air is passed through a heat exchanger that is mounted in front of the radiator before flowing to the inlet manifold. This heat exchanger is called the aftercooler.
Alternating Current (AC): The current flow changes regularly and constantly in the form of a sinusoidal wave. The pattern of the wave alternates about a central axis.
American Wire Gauge (AWG): A measure of the diameter of electrical wire. The smaller the AWG number, the larger the diameter of the wire. When the size of the wire increases, the capacity of the wire for carrying electrical current increases.
Atmospheric Pressure Sensor: An analog sensor that generates a signal that is proportional to the atmospheric air pressure in the crankcase. The sensor sends a signal to the ECM.
Boost Pressure Sensor: This sensor measures the inlet manifold air pressure from the turbocharger. The signal is sent to the ECM.
Breakout T Harness: A test harness that is designed to connect to an engine harness. The test harness allows normal operation of circuits while providing a breakout to the engine harness to measure signals.
Bypass Circuit: A circuit that is temporary to substitute for an existing circuit. The bypass circuit is used for test purposes.
Calibration: An electronic adjustment of a sensor signal.
CAT Data Link: A two-wire electrical connection for communication with other microprocessor based devices such as Caterpillar electronic monitoring displays. The data link is also the serial communication medium used for programming and troubleshooting with Caterpillar Electronic Service Tools.
Caterpillar Engine Monitoring: The part of the Caterpillar Electronic Engine Control that monitors Coolant Temperature, Oil Pressure, and Inlet Manifold Air Temperature to alert the operator that problems are detected. The Coolant Temperature, Inlet Manifold Air Temperature, and Oil Pressure Sensors are supplied by Caterpillar. These sensors are monitored by the ECM. After market engine monitoring systems do not interface with the Caterpillar Electronic Engine Control.
Code: Refer to Diagnostic Code.
Cold Mode: When the engine is cold, the timing is retarded and the low idle may be raised for engine protection, reduced smoke emissions and faster warm up time.
Component Identifier (CID): A two or three digit code which is assigned to each component to identify data that is sent through the data link to the ECM.
Coolant Temperature Sensor: This sensor detects the engine coolant temperature for Cold Mode operation and for Caterpillar Engine Monitoring.
Customer Specified Parameter: A parameter value that can be set by the customer.
Data Link: Refer to ATA Data Link, CAN Data Link, and CAT Data Link.
Desired RPM: An input to the electronic governor that is within the ECM. The electronic governor uses inputs from the Throttle Position Sensor, Engine Speed/Timing Sensor and Customer Parameters to determine the "Desired Engine Speed".
Diagnostic Code: Diagnostic codes indicate a malfunction or problem in the electronic control system of the engine. The diagnostic code is also called a diagnostic fault code.
Diagnostic Flash Code: The flash code is indicated by the number of flashes on the diagnostic lamp. The flash code indicates a malfunction or event that is detected by the ECM in the electronic control system.
Diagnostic Lamp: This lamp alerts the operator of the presence of an active diagnostic code. The lamp flashes the diagnostic code.
Direct Current (DC): Electrical current that flows in one direction.
Duty Cycle: Duty cycle is the ratio of the Time On versus the Total Time Off.
Electronic Control Analyzer & Programmer (ECAP): An electronic service tool developed by Caterpillar. This tool is used for programming and diagnosing a variety of Caterpillar electronic controls. The 3126B Marine Engine will not support ECAP.
Electronic Control Module (ECM): The ECM is a control computer for the engine that provides power to the engine electronics. The ECM receives inputs from sensors and other components that monitor the operation of the engine. The ECM accepts inputs that monitor and outputs that control or change to act as a governor to control the engine speed.
Electronic Engine Control: The complete electronic system that monitors and controls the operation of the engine under all conditions.
Electronic Technician (CAT ET): CAT ET is a software program that functions as a service tool used on a personal computer (PC).
Estimated Dynamic Timing: The ECM estimation of actual injection timing.
Event Code (EID): An event code indicates an abnormal operating condition of the engine. An event code does not necessarily indicate a problem that is within the electronic system.
Failure Mode Identifier (FMI): The FMI is a number that corresponds to the type of failure that the component experienced. The FMI is adopted from SAE J1587 standard practice diagnostics.
Flash Code: Flash codes are Caterpillar proprietary code numbers that are indicated by the flashing of the diagnostic lamp.
Flash Programming: Flash programming is a method of programming an ECM with an Electronic Service Tool. The data link is used for transmitting the program instead of replacing components that have different software.
Fuel Ratio Control (FRC): The FRC fuel position is a limit that is based on control of the fuel to air ratio. This control improves the control of emissions. When the ECM senses a higher boost pressure, the FRC increases the "FRC Fuel Pos" limit. A higher boost pressure allows more air in the cylinder. An increased "FRC Fuel Pos" allows more fuel into cylinder.
Fuel Position: The fuel position is an internal signal within the ECM that goes from the Electronic Governor to the Fuel Injection Control. The fuel position is determined by the Desired Engine Speed, the FRC Fuel Position, the rated fuel position and the engine speed.
Full Load Setting (FLS): The FLS is number that represents the adjustment of the fuel system that is made at the factory to set the maximum fuel delivery of the fuel system. The correct value for this parameter is stamped on the engine information ratings plate. This parameter must be programmed. Otherwise, a Diagnostic Code 253-02 Check Customer Or System Parameters and a flash code 56 will be generated.
Full Torque Setting (FTS): The FTS is similar to the Full Load Setting. The FTS must be programmed. Otherwise, a Diagnostic Code 253-02 Check Customer Or System Parameters and flash code 56 will be generated.
Harness: The harness is a wiring bundle that connects all components of the ECM.
Hertz (Hz): Hertz is a measure of frequency in cycles per second.
Histogram: A bar graph indicating the relative frequency of engine operation in specific operating ranges.
Hydraulic Electronically Controlled Unit Injector (HEUI): A HEUI is an fuel injector pump which is hydraulically actuated. The HEUI is a electronically controlled unit injector that combines the pumping, the electronic fuel metering and the fuel injecting elements in a single unit.
Inlet Air Manifold Pressure Sensor: This sensor measures the absolute air pressure at the inlet air manifold. The difference between the pressure at the inlet air manifold and the atmospheric pressure is the boost pressure.
Integrated Electronic Controls: The engine is designed to operate with electronic controls to control the operation of the engine. The engine will not operate without the electronic controls.
Logged Diagnostic Codes: Logged diagnostic codes are stored in the ECM memory. The codes are indicators of possible causes of intermittent problems. Refer to Diagnostic Code.
Oil Pressure Sensor: This sensor sends a signal to the ECM that indicates the engine oil pressure. The oil pressure sensor is part of the Caterpillar Engine Monitoring.
Open Circuit: An open circuit exists when an electrical wire or connection is broken or a switch is open. An open circuit prevents a signal or electrical current from reaching the intended destination
Original Equipment Manufacturer (OEM): An OEM is the manufacturer or customer of a machine or vessel in which a Caterpillar engine is installed.
Parameter: A parameter is a value that can be programmed in the ECM. This value determines the characteristics of operation or the behavior of an engine that is installed in a machine or vessel.
Password: A password is group of numeric or alphanumeric characters that must be entered before parameters can be changed. Customer passwords are set by the customer. Factory passwords are set by Caterpillar. Some engine specifications require factory passwords before the setting can be changed. Passwords are also required to clear certain diagnostic codes.
Personality Module or Ratings Personality Module: The module that contains all of the software instructions for the ECM and the performance maps for a specific family of engines. This module is located inside of the ECM.
Pulse Width Modulation (PWM): PWM is a signal that consists of variable width pulses at fixed intervals. The pulse width is a ratio of "Time On" versus total "Time Off". Refer to Duty Cycle.
Rated Fuel Position: This position indicates the maximum allowable fuel position. This fuel position is the longest injection pulse which produces the rated power of the engine. The rated fuel position is called "Rated Fuel Pos" on an Electronic Service Tool.
Reference Voltage: The reference voltage is a constant and regulated voltage supplied by the ECM to a sensor. The reference voltage is used by the sensor to generate a signal voltage.
Sensor: A sensor is a device used to detect and convert a change in pressure, temperature, or mechanical movement into an electrical signal.
Short Circuit: A short circuit occurs when an electrical circuit is unintentionally connected to an undesirable point. A wire that rubs against a metallic object until the insulation is worn so that the wire makes contact against the grounded object is an example of a short circuit.
Signal: A voltage or waveform that is generated by a device such as a sensor. The signal transmits information to the ECM.
Speed "burp": A sudden change in engine speed that is brief and unwanted.
Speed/Timing Sensor: A speed/timing sensor provides a Pulse Width Modulated Signal to the ECM. The ECM interprets the signal as the crankshaft position, the direction of rotation, and the engine speed.
Subsystem: A subsystem is a component or group of components that perform a function or an interrelated set of functions. A subsystem is part of a large system that is composed of additional subsystems.
Supply Voltage: A constant voltage that provides electrical power for the operation of the component. The supply voltage may be generated by the ECM or directly from the battery.
System Configuration Parameters: These parameters affect emissions or the power rating of a family of engines.
Throttle Position: The interpretation by the ECM of the signal from the Throttle Position Sensor.
Throttle Position Sensor: This electronic sensor is connected to an lever that sends a Pulse Width Modulated Signal to the ECM.
Timing Calibration: The adjustment of an electrical signal as a means of correcting the timing error between the crankshaft and the camshaft. Refer to Speed/Timing Sensor.
Total Tattletale: Total number of changes to all Customer Specified Parameters. The number is stored in the ECM.
Transducer: A device which converts a mechanical signal to an electrical signal. A transducer requires an external power source for operation.
Transmission Oil Pressure Sensor: The ECM monitors the oil pressure between 0 and 3100 kPa (0 and 450 psi). This sensor is located on the high pressure side of the marine gear.
Transmission Oil Temperature Sensor: The ECM monitors the oil temperature of the marine gear to a maximum of 120°C (248°F).
Warning Lamp: Indicates to the operator that the Caterpillar Engine Monitoring detected an abnormal operating condition.