Kohler Aegis ELH775 Service Manual page 37

Visual Inspection
1. Look for a damaged or disconnected sensor-to-
engine harness connection.
2. Look for damage to sensor lead wire or associated
engine wiring due to cutting, chaffi ng or melting on a
hot surface.
3. Disconnect sensor connector and look for corrosion
in connector.
4. Try reconnecting sensor and observe if problem has
cleared.
5. Correct any problems found during visual check.
Sensor Signal Observation
NOTE: Do not cut into or pierce sensor or engine
wiring to make this connection. Sensor
produces a very small signal. Corrosion or
damage to wiring could lead to an incorrect
signal because of repairs or contamination to
sensor.
1. Using a voltmeter or diagnostic software observe
voltage before engine is started. With key ON,
voltage should read about 1.0 volt. This voltage is
generated by ECU. If it is not present, disconnect
sensor and observe voltage at harness connector. If
voltage is now present, there is a short in sensor or
associated wiring and corrective action should be
taken. If voltage still is not present, there is a
problem with ECU or engine harness.
2. Reconnect sensor and start engine. Run engine at
suffi cient speed to bring sensor up to operating
temperature. Maintain for 1 to 2 minutes to ensure
that engine has gone closed loop. Once in closed
loop, sensor voltage should cycle between about
100 to 250 mv and 700 to 900 mv. If this cycling is
not observed, a determination must be made, if
problem is with engine or sensor.
3. Check engine harness for battery voltage on heater
circuit.
66 690 14 Rev. A
Removal Inspection
NOTE: Apply anti-seize compound only to threads.
Anti-seize compound will aff ect sensor
performance if it gets into lower shield of
sensor.
1. If sensor has heavy deposits on lower shield,
engine, oil, or fuel may be source.
2. If heavy carbon deposits are observed, incorrect
engine fuel control may be occurring.
3. If sensor is at room temperature, measure between
signal leads, black wire (Pin C) and grey wire (Pin D)
attached to sensor. If resistance is less than one
megohm, sensor has an internal short.
4. With sensor at room temperature measure heater
circuit resistance, purple wire (Pin A) and white wire
(Pin B), resistance should be 8.1-11.1 Ω.
5. If a damaged sensor is found, identify root cause,
which may be elsewhere in application. Refer to
Troubleshooting-Oxygen Sensor (O
6. A special "dry to touch" anti-seize compound is
applied to all new oxygen sensors at factory. If
recommended mounting thread sizes are used, this
material provides excellent anti-seize capabilities
and no additional anti-seize is needed. If sensor is
removed from engine and reinstalled, anti-seize
compound should be reapplied. Use an oxygen
sensor safe type anti-seize compound. It should be
applied according to directions on label.
KohlerEngines.com
EFI System
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