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

Governor System

FIELD INSTALLED UPDATED DESIGN Troubleshooting Electronic Governor

Failure Condition
Target/Selected Loss of GCU power
Speed not (B+ or Ground).
Maintained (Potentially
(Overspeed and/or Intermittent)
Underspeed) (No
hunt or surge)
Target/Selected Loss of ECU Speed
Speed Not Output (Speed
Maintained (Over Signal) (Potentially
speed and/or Under Intermittent)
speed) (No hunt or
surge)
No Start and/or Throttle fully closed.
ungoverned speed No throttle
below 1500 RPM movement.
No response to Loss of application
selected speed input supplied speed
control input signal.
Rapid hunting and/or Rev-limiting feature
surging active. (ECU
controlled limitation)
68
Possible Causes
When connection is lost, no DLA
movement will be seen. When
connection is restored, GCU will
command DLA to perform homing
sequence. Throttle closes then returns
to target speed position.
When connection is lost, no DLA
movement will be seen. When
connection is restored, throttle returns
to target speed position.
While cranking, GCU commands DLA
to open to a predetermined position. If
no movement is seen, engine may not
start due to closed throttle. If engine
starts, engine speed will be below 1500
RPM.
GCU regulates engine speed by
variable input voltage from a customer-
supplied source. When signal is lost,
engine speed will return to idle. When
connection is restored, throttle returns
to target speed position.
If maximum RPM limit (4500 RPM +) is
exceeded, ECU suppresses injection
signals, cutting off fuel fl ow. This
process repeats itself in rapid
succession, limiting operation to preset
maximum.
KohlerEngines.com
Equipment Observations 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 70 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.
62 690 05 Rev. E