8 KENR9126
Troubleshooting Section
The ECM adjusts injection timing and fuel pressure
for the best eng
ine performance, the best fuel
economy, and the best control of exhaust emissions.
Fuel Injectio
n
The flash file inside the ECM sets certain limits on
the amount of
fuel that can be injected.
The Fuel Ratio Control Limit is a limit that is based
on intake ma
nifold pressure and engine rpm. The
FRC Limit is used to control the air/fuel ratio in order
to control the engine's exhaust emissions. When
the ECM sens
es a higher intake manifold pressure,
the ECM increases the FRC Limit. A higher intake
manifold pressure indicates that there is more air in
the cylind
er. When the ECM increases the FRC Limit,
the ECM allows more fuel into the cylinder.
The Ra ted F
uel Limit 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 ou
tputs to conform to the power and torque
curves of a specifi c engine model.
These li
mits are in the flash file and these limits
cannot be changed by the operator.
Diagnostic Codes
When the
ECM detects an electronic system fault,
the ECM generates a diagnostic code. Also, the ECM
logsthediagnosticcodeinordertoindicatethetime
of the o
ccurrence of the fault. The ECM also logs the
number of occurrences of the fault. Diagnostic codes
are provided in order to indicate that the ECM has
detec
ted an electrical fault or an electronic fault with
the engine control system. In some cases, the engine
performance can be affected when the condition that
is cau
sing the code exists.
If the operator indicates that a performance problem
occu
rs, the diagnostic code may indicate the cause of
the fault. Use the electronic service tool to access the
diagnostic codes. The fault should then be corrected.
Event Codes
Eve
nt Codes are used to indicate that the ECM has
detected an abnormal engine operating condition.
The ECM will log the occurrence of the event code.
Thi
s does not indicate an electrical malfunction
or an electronic malfunction. For example, if the
temperature of the coolant in the engine is higher
th
an the permitted limit, then the ECM will detect the
condition. The ECM will then log an event code for
the condition.
Programmable P
arameters
Certain parameters that affect the engine operation
may be changed
with electronic service tools. The
parameters are stored in the ECM and some of the
parameters are protected from unauthorized changes
by passwords.
These parameters are System
Configuration Parameters.
System Config
uration Parameters are set at the
factory. System Configuration Parameters affect the
emissions or the power ratings within the engine.
Factory pas
swords must be obtained and used in
order to change some of the System Configuration
Parameters. Examples of these parameters are FLS
and FTS.
Passwords
System Configuration Parameters are protected by
factory pa
sswords. Factory passwords are calculated
on a computer system that is available only to
Perkins distributors. Since factory passwords contain
alphabet
ic characters, only an electronic service
tool may change System Configuration Parameters.
System Configuration Parameters affect the power
rating o
r the emissions.
Refer to Troubleshooting, “Programming Parameters”
and Trou
bleshooting, “Factory Passwords”.
i04012391
Glossary
Active Diagnos tic Code – An active diagnostic
code alerts the operator or the service technician that
an electronic system malfunction is currently present.
Refer to the term “Diagnostic Code” in this glossary.
Adaptive Trim – This is a software process that is
performed in the Electronic Control Module (ECM)
that optimizes engine performance.
Before Top Center (BTC) – BTC is the 180 degrees
of crankshaft rotation before the piston reaches the
top dead center position in the normal direction of
rotation.
Breakout Harness – A breakout harness is a
test harness that is designed to connect into the
engine harness. This connection allows a normal
circuit operation and the connection simultaneously
provides a Breakout T in order to measure the
signals.
Bypass Circuit – A bypass circuit is a circuit that is
used as a substitute circuit for an existin g circuit. A
bypass circuit is typically used as a test circuit.
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