Perkins NJ Series Troubleshooting Manual page 11

SENR9982-01
Intake Manifold Pressure Sensor – The Intake
Manifold Pressure Sensor measures the pressure
in the intake manifold. The pressure in the intake
manifold may be different to the pressure outside
the engine (atmospheric pressure). The difference
in pressure may be caused by an increase in air
pressure by a turbocharger (if equipped).
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.
J1939 CAN Data Link – This data link is a SAE
standard diagnostic communications data link that
is used to communicate between the ECM and the
electronic devices.
Logged Diagnostic Codes – Logged diagnostic
codes are codes which are stored in the memory.
These codes are meant to be an indicator of possible
causes for intermittent problems. Refer to the
term "Diagnostic Code" in this glossary for more
information.
OEM – OEM is an abbreviation for the Original
Equipment Manufacturer. This is the manufacturer of
the machine or the vehicle that uses the engine.
Open Circuit – An open circuit is a condition that is
caused by an open switch, or by an electrical wire
or a connection that is broken. When this condition
exists, the signal or the supply voltage can no longer
reach the intended destination.
Parameter – A parameter is a value or a limit that
is programmable. This helps determine specific
characteristics or behaviors of the engine.
Password – A password is a group of numeric
characters or a group of alphanumeric characters
that is designed to restrict access to parameters. The
electronic system requires correct passwords in order
to change some parameters (Factory Passwords).
Refer to Troubleshooting, "Factory Passwords" for
more information.
Personality Module – See "Flash File".
Power Cycled – Power cycled happens when power
to the ECM is cycled: ON, OFF, and ON. Power
cycled refers to the action of cycling the keyswitch
from any position to the OFF position, and to the
START/RUN position.
Primary Speed/Timing Sensor – This sensor
determines the position of the crankshaft during
engine operation. If the primary speed/timing
sensor fails during engine operation, the secondary
speed/timing sensor is used to provide the signal.
Pulse Width Modulation (PWM) – The PWM is a
signal that consists of pulses that are of variable
width. These pulses occur at fixed intervals. The ratio
of "TIME ON" versus total "TIME OFF" can be varied.
This ratio is also referred to as a duty cycle.
Illustration 3
Rated Fuel Limit – This is a limit that is based on
the power rating of the engine and on the engine rpm.
The Rated Fuel Limit enables the engine power and
torque outputs to conform to the power and torque
curves of a specific engine model. These limits are in
the flash file and these limits cannot be changed.
Reference Voltage – Reference voltage is a
regulated voltage and a steady voltage that is
supplied by the ECM to a sensor. The reference
voltage is used by the sensor to generate a signal
voltage.
Relay – A relay is an electromechanical switch. A
flow of electricity in one circuit is used to control the
flow of electricity in another circuit. A small current or
voltage is applied to a relay in order to switch a much
larger current or voltage.
Secondary Speed/Timing Sensor – This sensor
determines the position of the camshaft during engine
operation. If the primary speed/timing sensor fails
during engine operation, the secondary speed/timing
sensor is used to provide the signal.
Sensor – A sensor is a device that is used to
detect the current value of pressure or temperature,
or mechanical movement. The information that is
detected is converted into an electrical signal.
Short Circuit – A short circuit is a condition that has
an electrical circuit that is inadvertently connected to
an undesirable point. An example of a short circuit
is a wire which rubs against a vehicle frame and
this rubbing eventually wears off the wire insulation.
Electrical contact with the frame is made and a short
circuit results.
Signal – The signal is a voltage or a waveform that
is used in order to transmit information typically from
a sensor to the ECM.
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Troubleshooting Section
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