New Installed Updated Design Troubleshooting Electronic Governor - Kohler Command PRO EFI Series Service Manual

NEW INSTALLED UPDATED DESIGN Troubleshooting Electronic Governor

Failure Condition
Target/Selected
Speed not
Maintained
(Overspeed and/or
Underspeed) (No
hunt or surge)
Target/Selected
Speed Not
Maintained (Over
speed and/or Under
speed) (No hunt or
surge)
No Start and/or
ungoverned speed
below 1500 RPM
No response to
selected speed input
Rapid hunting and/or
surging
62 690 05 Rev. E
Possible Causes
Loss of GCU power When connection is lost, no DLA
(B+ or Ground). movement will be seen. When
(Potentially connection is restored, GCU will
Intermittent) command DLA to perform homing
sequence. Throttle closes then returns
to target speed position.
Loss of ECU Speed When connection is lost, no DLA
Output (Speed movement will be seen. When
Signal) (Potentially connection is restored, throttle returns
Intermittent) to target speed position.
Throttle fully closed. While cranking, GCU commands DLA
No throttle to open to a predetermined position. If
movement. no movement is seen, engine may not
start due to closed throttle. If engine
starts, engine speed will be below 1500
RPM.
Loss of application GCU regulates engine speed by
supplied speed variable input voltage from a customer-
control input signal. supplied source. When signal is lost,
engine speed will return to idle. When
connection is restored, throttle returns
to target speed position.
Rev-limiting feature If maximum RPM limit (4500 RPM +) is
active. (ECU exceeded, ECU suppresses injection
controlled limitation) signals, cutting off fuel fl ow. This
process repeats itself in rapid
succession, limiting operation to preset
maximum.
Equipment Observations
KohlerEngines.com
Governor System
Inspection/Testing
Test GCU power (red/B+)
wire for supply voltage and
test ground circuit. Inspect
all connections and wires
for poor connection.
Repair and replace as
required.
View GCU blink codes for
potential trouble code.
Inspect all connections
and wires for poor
connection. Repair and
replace as required.
Using EFI Diagnostic
Software, observe TPS
value for movement, check
system power, physical
binding, and wiring etc.
Conduct speed input wire
(red w/yellow tracer)
voltage test. (Refer to test
description on page 77 for
more information)
See rows 1 and 2, view
throttle position, observe
for movement. Test DLA
function using stepper
motor controller tool. Refer
to Tools and Aids.
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