Governor System
58 62 690 05 Rev. EKohlerEngines.com
ORIGINAL DESIGN GCU/Harness Diagnostics and Troubleshooting
NOTE: It is important to use proper sized probes to perform these tests. Probes that are incorrect size can damage
connector or harness plug.
Original design features a separate GCU and wiring harness that can be separated and tested for power and
ground. This design is easily identifi ed by 2 screws that secure DLA actuator bracket. See page 56 for an engine with
original design electronic governor.
ORIGINAL DESIGN Ground and Power Tests
1. Switch key to OFF position.
2. Remove GCU from bracket and unplug wiring
harness.
These two tests check for power and ground supply
to GCU. If either test fails, check if harness, electrical
connections, or electrical system need repair.
Test 1 Probe Location (Original Design)
A
A Probe Location for Ground Test 1.
Test 1: Identify probe location in connector. Using a
continuity tester, check for a good ground. If ground is
faulty, inspect unit ground, battery ground, connectors,
and wiring harness. Clean or fi x connections or replace
any faulty parts.
If test 1 checks OK, locate probe location in connector,
and check using test 2.
Test 2 Probe Location (Original Design)
A
A Probe Location for Voltage Test 2.
Test 2: Identify probe location in connector. Using a
12 volt meter test for voltage. Turn key switch to ON
position. Voltage should be within +/- 1 volt of battery
voltage. If voltage is within +/- 1 volt of battery voltage,
harness is OK, replace GCU. If not within +/- 1 volt of
battery voltage, check connections and replace wiring
harness if necessary.
ORIGINAL DESIGN Ohms Tests
1. Remove GCU from bracket and unplug wiring
harness.
These two tests are for measuring resistance of DLA
circuit that sends a signal to GCU. If either test fails,
DLA is no good and should be replaced. If both tests are
good, DLA is neither shorted or open, it is good. Another
component, connection, or input is most likely at fault.
Test 1 Probe Location (Original Design)
A
A Probe Locations for OHMs Test 1.
Test 1: Identify probe locations in connector. Using a
digital multi-meter set to lowest scale (0-200 ohms),
place probes onto harness making sure of a good
connection. Resistance should be between 47.7 and
58.3 ohms.
If test 1 checks OK, locate wire ends in connector and
check using test 2.
Test 2 Probe Location (Original Design)
A
A Probe Locations for OHMs Test 2.
Test 2: Identify probe locations in connector. Using a
digital multi-meter set to lowest scale (0-200 ohms),
place probes onto harness making sure of a good
connection. Resistance should be between 47.7 and
58.3 ohms.
If either test 1 or 2 fail resistance test, fault could also
be caused by a break/cut in wiring harness. Inspect and
test for a potential harness issue prior to replacing DLA
assembly.
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