
RENR9348-01 167
Troubleshooting Section
•
Not OK – The throttle signal is not present at the
speed control.
Repair: There is a problem with the speed control.
Replace the sp
eed control. Verify that the problem
is no longer present.
STOP.
Test Step 5. Check the PWM Signal at the
Engine Interface Connector
A. Disconnect the engine interface connectors.
B. Remove the wi
res from terminal locations 15
(digital return) and 21 (rated speed) on the side
of the engine interface connector that is from the
speed contro
l.
C. Connect the engine interface connectors.
D. Use a multimeter that is capable of reading a
percent duty cycle in order to measure the output
at the wires
that have been removed from terminal
locations 15 and 21 at the engine interface
connectors.
E. Restore electrical power to the ECM.
F. Monitor the
output of the percent duty cycle from
these wires on the multimeter. Turn the speed
adjust potentiometer from the low setting to the
high setti
ng.
G. Remove electrical power from the ECM.
Restore the wiring to the original configuration.
Expected R
esult:
The throttle signal is reaching the engine interface
connector
s.
Results:
•
OK – The throttle signal is reaching the connector.
Proceed to Test Step 6.
•
Not OK – The throttle signal is not reaching the
connector.
Repair: Repair the connectors or wiring and/or
replace the connectors or wiring between the
speed con
trol and the engine interface connector.
STOP.
Test Step 6. Check the PWM Signal at the
ECM
A. Disconn
ect the J1/P1 ECM connectors.
B. Remove the wires from terminals P1-5 (digital
return) and P1-
66 (throttle signal) at the ECM
connector.
C. Connect the J1
/P1 ECM connectors.
D. Use a multimeter that is capable of reading a
percent duty c
ycle in order to measure the output
at the wires from terminals P1-5 (digital return)
and P1-66 (throttle signal) at the ECM connector.
E. Restore electrical power to the ECM.
F. Monitor the o
utput of the percent duty cycle from
the speed control on the multimeter . Turn the
speed adjust potentiometer from the low setting
to the high se
tting.
G. Remove electrical power from the ECM.
Expected Result:
The throttle
signal is present at the connector.
Results:
•
OK – The throttle signal is present at the
connector.
Repair: The ECM is not detecting the signal
correctly. Replace the ECM. Refer to the diagnostic
functional
test Troubleshooting, “Replacing the
ECM” for details.
STOP.
•
Not OK – The throttle signal is not present at the
ECM connec
tor.
Repair: The problem is in the harness between
ECM connec
tor P1 and the engine interface
connectors. There may be a problem with a
connector. Repair the connectors or wiring and/or
replace th
e connectors or wiring.
STOP.
i02418874
Start Relay Circu it - Test
SMCS Code: 1426-038
System Ope
ration Description:
Use this procedure to troubleshoot any suspect
problems
with the circuit for the start relay.
This procedure covers the following diagnostic codes:
•
444-05 Start Relay open circuit
•
444-06 Sta
rt Relay short to ground