
RENR9348-01 163
Troubleshooting Section
C. Disconnect the P2 connector.
D. Remove the supply wire from the terminal location
for the suspect injector at the ECM connector.
Install the ju
mper wire into this socket.
E. Connect the J2/P2 ECM connectors.
F. Verify that the ECM will detect an open circuit for
the suspect injector:
a. Ensure that the jumper wire is not in contact
with a ground source or another circuit. Do not
touch the jum
per wire during the test. A strong
electrical shock hazard is present at the jumper
wire while the test is running.
b. Restore the electrical power to the ECM.
c. Perform the “
Injector Solenoid Test” at least
two times.
d. Remove the el
ectrical power from the ECM.
Cat ET dis plays “Open” for the two injectors
that share t
he supply wire.
G. Verify that the ECM detects a short circuit for the
suspect inj
ector:
a. Connect the jumper wire to the engine ground
stud. Do not
touch the jumper wire during the
test. A strong electrical shock hazard is present
at the jumper wire while the test is running.
b. Restore the electrical power to the ECM.
c. Perform th
e “Injector Solenoid Test” at least
two times.
d. Remove the
electrical power from the ECM.
Cat ET displays “Short” for the two injectors
that share
the supply wire.
Expected Result:
Cat ET displays the correct status for each test circuit.
Results:
•
OK – The ECM detects the correct status of the
circuit.
Repair: The ECM is OK. The problem is in the
engine har
ness or in a connector. Inspect the
connectors for moisture and for corrosion. Repair
the wiring and/or the connector, when possible.
Replace p
arts, if necessary. Clear all diagnostic
codes after you complete this test step.
STOP.
•
Not OK – The ECM does not detect the correct
status of the ci
rcuit.
Repair: There is a problem with the ECM. Replace
the ECM. Refer
to Tr oubleshooting, “Replacing the
ECM”. Verify that the problem is resolved.
STOP.
i02415737
Speed Control
- Test
SMCS Code: 1439-038; 1913-038
System Operation Description:
The load shari
ng module provides a throttle signal to
the engine’s Electronic Control Module (ECM). The
output for rated speed is a pulse width modulated
signal (PWM)
at a constant frequency. The speed
signal varies with the position of the speed adjust
potentiometer. The output signal is referred to as a
duty cycle o
r as a PWM signal. The output signal
is expressed as a percentage between 0 and 100
percent for the speed adjust.
Note: Desired speed can be adjusted from 1141 to
1621 rpm over the range of the PWM signal for a 50
Hz applicat
ion. For a 60 Hz application, the desired
speedcanbeadjustedfrom1369to1945rpmover
the range of the PWM signal.
The ECM calculates the desired engine rpm from
the throttle signal and the droop signal. The throttle
signal is v
alid when the duty cycle is in the range
of 5 to 95 percent. If the ECM determines that the
throttle signal is invalid, the engine rpm will be set to
the progr
ammed low idle.