0302509 JOHNSON SCREW,By-pass cover

two-wire electrical connection for communication with other microprocessor based devices that are compatible with the American Trucking Association and SAE Standards (J1587 and J1708) such as trip recorders, electronic dashboards, powertrain controls, and maintenance systems. The Data Link is also the serial communication medium used for programming and troubleshooting with Caterpillar devices.Active Diagnostic CodeDescribes a condition that is currently present to alert the driver or service technician of an abnormal engine operation parameter. Refer to Diagnostic Fault Code.Aftermarket DeviceAs used here, a device or accessory installed by the customer or vehicle OEM after the engine is delivered.Air-To-Air Aftercooler (ATAAC)A means of cooling intake air after the turbocharger, using ambient air for cooling. The intake air is passed through an aftercooler (heat exchanger) mounted in front of the radiator before going to the intake manifold.Alternating Current (AC)The direction of current flow changes (alternates) regularly and constantly in a circuit.American Wire Gauge (AWG)A measure of the diameter (and therefore the current carrying ability) of electrical wire. The smaller the AWG number, the larger the wire.Before Top Center (BTC)The 180 degrees of crankshaft rotation before the piston reaches the very top of its travel (normal direction of rotation).Boost Pressure SensorThis sensor measures inlet manifold air pressure and sends a signal to the ECM.Bypass CircuitA circuit, usually temporary, to substitute for an existing circuit, typically for test purposes.CalibrationAs used here, is an electronic adjustment of a sensor signal.Caterpillar Engine MonitoringThe part of the Caterpillar Electronic Engine Control that monitors Coolant Temperature to alert the operator of detected problems. The Coolant Temperature Sensor is supplied by Caterpillar and monitored by the ECM. After market engine monitoring systems do not interface with the Caterpillar Electronic Engine Control.Check Engine LampSometimes referred to as the "Diagnostic Lamp", it is used to alert the operator of the presence of an active event and is used to flash a diagnostic code.Clutch SwitchThis OEM supplied and installed switch is typically a limit switch mounted near the pedal and is usually adjustable. This switch is normally closed with the pedal released. Depressing the clutch will open the circuit.CodeRefer to Diagnostic Fault Code and Diagnostic Event Code.Cold ModeA mode of engine operation where the timing is retarded and the low idle may be raised for engine protection, reduced smoke emissions and faster warm up time.Coolant Temperature SensorThis sensor detects the engine coolant temperature for Cold Mode operation and Caterpillar Engine Monitoring (if Engine Monitoring is not programmed OFF).Cruise Control RangeThe range that the cruise control can operate within. Usually limited to the speed range anticipated on the open road. It is programmable using the Low Cruise and High Cruise Limits.Customer Specified ParameterA parameter value that can be changed and whose value is set by the customer. Protected by Customer Passwords.Data LinkRefer to ATA Data Link.Desired RPMAn input to the electronic governor within the ECM. The electronic governor uses input from the Throttle Position Sensor, Engine Speed/Timing Sensor and Customer Parameters to determine "Desired RPM".Diagnostic Event CodeThese codes indicate an event that describe an abnormal engine condition, such as an Idle Shutdown Occurrence. They are not necessarily (or usually) an indication of problems within the Electronic System.Diagnostic Fault CodeSometimes referred to as a "fault code". These codes indicate an electronic system malfunction or problem with the truck engine Electronic System.Diagnostic Flash CodeThese codes are flashed out using the Check Engine/Service Engine Soon Lamp to indicate an electronic system malfunction or an event detected by the Electronic System ECM.Diagnostic LampSometimes referred to as the "check engine lamp", it is used to alert the operator of the presence of an active diagnostic code.Direct Current (DC)The type of current where the direction of current flow is consistently in one direction only.Dual Coil Vehicle Speed SensorA magnetic pickup that senses movement of the teeth on the output shaft of the transmission. It contains two coils, one to supply a signal to the vehicle speedometer, and one for the vehicle speed buffer.Duty CycleRefer to Pulse Width Modulation.Electronic Control Module (ECM)The engine control computer that provides power to the truck engine electronics. It accepts inputs that monitor and outputs that control or change to act as a governor to control engine rpm.Electronic Engine ControlThe complete electronic system that monitors and controls engine operation under all conditions.Electronically Controlled Unit InjectorThe injection pump which is mechanically actuated, electronically controlled unit injector combining the pumping, electronic fuel metering and injecting elements in a single unit.Electronic Technician (CAT ET)A software program to run on a service tool like a personal computer (PC).Engine Oil Temperature SensorThis sensor detects the engine oil temperature for Cold Mode operation.Engine Speed/Timing SensorProvides a variable amplitude and Pulse Width Modulated Signal to the ECM, which the ECM interprets as crankshaft position and engine speed.Exhaust Brake RelayThe brakes' solenoids are driven by an OEM installed relay, which is driven by the ECM.Failure Mode Identifier (FMI)Type of failure the component experienced (adopted from SAE standard practice J1587 diagnostics).(FMI) Description0 Data valid but above normal operational range1 Data valid but below normal operational range2 Data erratic, intermittent, or incorrect3 4 Voltage below normal or shorted low5 Current below normal or open circuit6 Current above normal or grounded circuit7 Mechanical system not responding properly8 Abnormal frequency, pulse width, or period9 Abnormal update10 Abnormal rate of change11 Failure mode not identifiable12 Defective device or component13 Uncalibrated device or component14/15 Reserved for future assignmentFast IdleFast Idle RPM determines the preset Fast Idle engine rpm as controlled using the Fast Idle Enable Switch. Fast Idle operates similar to cruise control, except it governs engine rpm with the vehicle stationary, or at low vehicle speeds.Flash Code (FC)The Caterpillar proprietary code numbers which are flashed out on the diagnostic lamp.Flash ProgrammingA way of programming or updating an ECM with an Electronic Service Tool over the data link instead of replacing components.Fuel Ratio Control (FRC)FRC Fuel Pos. - is a limit based on control of the fuel-air ratio and is used for emissions control purposes. When the ECM senses a higher boost pressure (more air into cylinder), it