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Electronic Governor Control
The governor controls engine rpm within a safe and stable
operating range.
The low idle governor prevents engine rpm from dropping
below a stable speed to prevent stalling when various loads are
demanded on the engine.
The high idle governor prevents engine rpm from going above a
safe speed that would cause engine damage.
Electronic Service Tool (EST) Interface
Engines are equipped with the EST interface for communication
between the Engine Control Module (ECM) and the EST.
CAN is a J1939 serial bus system, also know as the Drivetrain
Datalink. The public Controller Area Network (CAN) provides a
communication link between all connecting modules by sending
and receiving messages.
The EST with ServiceMaxx™ software communicates with the
ECM through the EST interface. The EST, through the public
CAN, is able to retrieve Diagnostic Trouble Codes (DTCs), run
diagnostic tests, and view Parameter Identifiers (PIDs) from all
inputs and outputs of the ECM.
CAN public supports the following functions:
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Transmission of engine parameter data
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Transmission and clearing of DTCs
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Diagnostics and troubleshooting
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SECTION 1 – ENGINE SYSTEMS
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Electronic Speedometer and Tachometer
The engine control system calibrates vehicle speed.
calculated vehicle speed is a function of transmission tail shaft
speed, number of teeth on the tail shaft, rear axle ratio, and tire
revolutions per mile. Use the Electronic Service Tool (EST) with
ServiceMaxx™ software to program new speed calibrations into
the ECM.
The tachometer signal is generated by the ECM by computing
signals for the Camshaft Position (CMP) sensor and Crankshaft
Position (CKP) sensor.
Engine Crank Inhibit (ECI)
ECI prevents starter engagement when the engine is running or
when the transmission is in gear.
Event Logging System
The event logging system records engine operation above
maximum rpm (over speed), low coolant level, high coolant
temperature, or low oil pressure. The readings for the odometer
and hourmeter are stored in the ECM memory at the time of an
event and can be retrieved using the EST.
Programming performance parameter values
Programming engine and vehicle features
Programming calibrations and strategies in the ECM
The
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