Troubleshooting

8 RENR2696-01
Troubleshooting Section
At start-up, the ECM determines the top dead
center positio
n of the number 1 cylinder from the
speed/timing sensor in the fuel injection pump.
The ECM decides when fuel injection should occur
relative to th
e top dead center position. The ECM
provides the signal to the fuel injection pump spill
valve which stops fuel flow to the low pressure
side. The ECM
then forces fuel to flow to the fuel
injector nozzles at the desired time. The ECM adjusts
timing for the best engine performance, the best fuel
economy and
the best control of exhaust emissions.
Actual timing cannot be viewed with an electronic
service tool. Also, the desired timing cannot be
viewed with
an electronic service tool.
Fuel Injection
The personality module inside the ECM sets certain
limits on the amount of fuel that can be injected. The
FRC Limit is
a limit that is based on intake manifold
air pressure and engine rpm. The FRC Limit is used
to control the air/fuel ratio in order to control the
engine’s e
xhaust emissions. When the ECM senses
a higher intake manifold air pressure, the ECM
increases the FRC Limit. A higher intake manifold
air press
ure indicates that there is more air in the
cylinder. When the ECM increases the FRC Limit, the
ECM allows more fuel into the cylinder.
The Rated Fuel 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 outputs to conform to the power and torque
curves of a specific engine model.
These limits are in the personality module and these
limits cannot be changed.
Diagnostic Codes
When the ECM detects an engine problem, the ECM
generates a diagnostic code. Also, the ECM logs
the dia
gnostic code in order to indicate the time of
the problem’s occurrence. The ECM also logs the
number of occurrences of the problem. There are
two typ
es of diagnostic fault codes. There are fault
codes and event codes.
Diagno
stic Fault Codes
Diagnostic fault codes are provided in order to
indic
ate that an electrical problem or an electronic
problem has been detected by the ECM. In some
cases, the engine performance can be affected when
the co
ndition that is causing the code exists. More
frequently, the operator cannot detect any difference
in the engine performance.
If the operator indicates that a performance problem
occurs, the dia
gnostic code may indicate the cause
of the problem. Use either a laptop computer or a
hand held diagnostic tool to access the diagnostic
codes. The pro
blem should then be corrected.
If the operator does not indicate a problem with
theenginepe
rformance and a diagnostic code is
logged by the ECM. This situation indicates that
the ECM detected an abnormal engine condition,
but the abnor
mal condition did not affect engine
performance. In this situation, the system has no
faults except when either of the following conditions
exist:
•
There are several occurrences of the diagnostic
code in a ver
y short period of time.
•
The ECM is indicating an active code at the
present tim
e.
Diagnostic Event Codes
Diagnostic event codes are used to indicate that
some operational problem has been detected in
the engine
by the ECM. This does not indicate an
electronic malfunction.
Programmable Parameters
Certain pa
rameters that affect the engine operation
may be changed with electronic service tools.
The parameters are stored in the ECM, and the
parameter
s are protected from unauthorized changes
by passwords. These parameters are System
Configuration Parameters.
System Configuration Parameters are set at the
factory. System Configuration Parameters affect
emission
s or power ratings within the engine. Factory
passwords must be obtained and factory passwords
must be used to change the System Configuration
Paramet
ers.
Passwor
ds
System Configuration Parameters are protected by
factory
passwords. Factory passwords are calculated
on a computer system that is available only to
Perkins distributors. Since factory passwords contain
alphab
etic characters, only an electronic service
tool may change System Configuration Parameters.
System Configuration Parameters affect the power
rating
or t he emissions.
Refer to Troubleshooting, “Programming Parameters”
and Tro
ubleshooting, “Factory Passwords”.