40019 87 Mercury SCREW, COVER TO SEPARATOR

in the air conditioning system and (opens or closes) electrical contacts depending on this pressure to turn the cooling fan ON. This switch may or may not be connected to the ECM.ATA (American Trucking Association) Data LinkA 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.After Market 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.Anti-Lock Brake System (ABS)Vehicle brake system that attempts to reduce wheel skid during brake operation. A power train electronic control can turn off the engine retarder if necessary, or signal the engine ECM to turn the engine retarder OFF.Atmospheric Pressure SensorAnalog sensor generates a signal proportional to atmospheric (barometric) air pressure in the crankcase and sends a signal to the ECM.Auxiliary Retarder RelayThe brakes' solenoids are driven by an OEM installed relay, which is driven by the ECM.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 Driver Information Display (CAT ID)A digital readout for operator viewing of vehicle and ECM monitored performance parameters.Caterpillar Engine MonitoringThe part of the Caterpillar Electronic Engine Control that monitors Coolant Temperature, Oil Pressure, Intake Manifold Air Temperature and Coolant Level to alert the operator of detected problems. The Coolant Temperature, Intake Manifold Air Temperature, and Oil Pressure Sensors are supplied by Caterpillar and monitored by the ECM. The Coolant Level Sensor is Vehicle OEM installed, but still 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.CodeSee Diagnostic Fault 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 Level SensorThis OEM installed sensor detects the absence/presence of coolant at the probe and sends a signal to the ECM. Coolant Temperature SensorThis sensor detects the engine coolant temperature for Cold Mode operation and Caterpillar Engine Monitoring (if Engine Monitoring is not programmed OFF).Cooling Fan RelayThis OEM supplied and installed relay is controlled by the ECM. The ECM controls the cooling fan relay