62-11389
7
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81
Alarm
NO.
Steps
Alarm/Cause
Corrective Action
P174 CHECK LOW SPEED RPM
•
TRIGGER–ON in Test #5: With Speed Relay turned off, engine speed is NOT between 1250 and
1450 rpm.
•
TRIGGER–ON in Test #7: 15 seconds after the High Speed Pretrip Test #6, engine speed has NOT
dropped back to the low speed range (within 15 seconds) as shown above.
Note: This test will be skipped if the RPM sensor alarm (A130) is active.
•
UNIT CONTROL:
Engine Operation: Pretrip will fail and display
“PRETRIP FAIL AND COMPLETED”.
Standby Operation: This test is not made.
•
RESET CONDITION: Auto Reset if Pretrip is started again or alarm may be manually reset via
keypad or by turning the unit off then back on again.
NOTE: Follow the steps below until a problem is found. Once a repair or correction has been made, clear the
alarm(s). (See Note 1 page 7
−
2.) Operate the unit through the appropriate modes to see if any active alarm
occurs. Continue with the steps below as necessary.
1
Check Model Number
Verify that the model number on the
nameplate matches the model num-
ber shown in the microprocessor Un-
it Data.
Enter the correct number in Configurations. Refer to
Section 5.2.1
2
Check the fuel/speed actuator
Check FSA plunger.
Must move in and out freely.
3
Verify low speed operation (See Note 5 page 7
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2)
a. Set Functional Parameter “LOW
SPEED START” for a high number
(30 to 90) then start the unit.
Set Functional Parameter back
to original setting after
completing repairs.
LED 27 must be OFF.
b. Check operation of Speed Relay
LED.
LED 27 must be OFF.
c. Check voltage to FSA.
Must be 0 VDC.
d. Check for 12 VDC on engine speed
control unit (ENSCU) pin 22.
Must be 12 VDC.
4
Check for proper voltage to the Engine Speed Control Unit (ENSCU) Pin 16 Based On
Requested Speed From The Microprocessor
Check voltage at pin 16 with unit run-
ning.
Must be 0 VDC.
5
Check engine RPM
a. Check actual engine RPM using
hand held tachometer.
Check Speed Control System, refer to Section 9.5
b. Compare actual RPM with those
shown on display.
Both readings within
±
50 RPM.
6
Check engine intake air system
a. Check air cleaner indicator.
Flag must not be visible.
b. Inspect air intake system.
Hoses & tubes in good condition.
No kinks or restrictions.
7
Check engine exhaust system
Inspect the exhaust system.
Must be clear and unobstructed.
