Kubota WG1605-E3 Diagnostic Manual page 50

WG1605-G-E3,WG1605-L-E3,WG1605-GL-E3, DM
(Continued)
3. Pre-Catalyst EGO Sensor Check (CL Test State=
Pre-cat voltage test & Pre-cat BM test)
• The purpose of this portion of the test is:
1. To validate that the pre-catalyst EGO sensor
feedback is perturbating and providing feedback that
correlates to commanded fueling excursions.
2. Attempt to identify leaks within the pre-catalyst
sensor assembly and/or the exhaust system and/or
identify significant fuel delivery problems.
a) Once all pre-catalyst EGOs have reached the
active threshold ('Pre-cat EGO impedance active
threshold') closed-loop is activated and fueling
perturbation begins at the nominal fueling target
defined in the test setup parameters. During this
time, adaptive learn is disabled and the fueling
error is monitored
closed-loop system validates a certain number of
EGO switches, the total fueling correction
(CL_BM+A_BM) is compared to allowable
fueling correction limit for the test ('CL+ adapt
multiplier max value').
b) If the fueling correction is within the limits defined
in the calibration, the CL pre-cat test status will
indicate "Test Finished: Passed".
c) This portion of the test will fail if the EGO fails to
generate the required number of switching
cycles or if the fueling correction is outside of the
acceptable limits. The CL pre-cat test status will
indicate "Pre-cat EGO non-responsive" or
"Pre-cat EGO fueling error" status, respectively.
In addition, the
High/Low" fault will be generated if this check
fails.
4. Post-Catalyst EGO Heater Diagnosis (CL Test
State= Post-cat heater test & post-cat power test)
• The purpose of this portion of the test is:
1. To validate that the post-catalyst EGO heater
element(s) are capable of heating the sense
element(s) to a useable state.
2. To validate that the post-catalyst sense element(s)
are operating at the desired temperature.
a) Upon successful completion of the pre-catalyst
EGO test checks, the system begins to monitor
the post-catalyst sensor(s). The first check is to
monitor EGO impedance feedback and verify
impedance ≤ 'EGO impedance active threshold';
this stage runs up to the maximum run time in the
'EGOZ Heater-Control Target Impedance /
Voltage Limit Schedule'
Additional Wait Time'. If this check fails for any of
the post-catalyst sensors the CL post-cat test
status will indicate "Post-cat EGO Lazy" and the
appropriate EGO Lazy fault for the sensor(s) is
set.
b) In addition, the
impedance feedback
impedance is equal to the fully warm 'EGOZ
Impedance Target' + 'EGO Heater Impedance
Max Error'. If any EGO impedance fails to reach
(CL_BM). Once the
appropriate "Closed-Loop
+ 'EGO Heater
system monitors EGO
and verifies that
the final target plus the impedance error
tolerance the heater power is deemed low, the
CL post-cat test status "Post-cat EGO Power
Low" is generated, and the appropriate EGO
Lazy fault for the sensor(s) is set. Once all
post-catalyst EGOs have reached the active
threshold ('Post-cat EGO impedance active
threshold) the rich/lean test is run on the
post-catalyst sensors.
5. Post-Catalyst EGO Sensor Check (CL Test
State= Post-cat rich test & Post-cat lean test)
• The purpose of this portion of the test is:
1. To validate that the post-catalyst EGO sensor
feedback is changing as a result of significant
changes in pre-catalyst fueling.
a) Command nominal fueling while applying the
fueling multiplier(s) generated during the 'CL
pre-cat voltage test' mode (step 3a).
b) Command a rich open-loop fueling command as
defined in the calibration and monitor the
post-catalyst EGO voltage feedback to verify that
the sensor's rich feedback is within tolerance.
c) Command a lean open-loop fueling command as
defined in the calibration and monitor the
post-catalyst EGO voltage feedback to verify that
the sensor's lean feedback is within tolerance.
d) If the post-catalyst EGO voltage feedback is
within the limits defined in the calibration, the CL
post-cat test status will indicate "Test Finished:
Passed" and the CL Test State will indicate
"Finished". If post-cat voltage(s) fall outside of
the rich/lean limits, CL post-cat test status will
indicate "Post-cat EGO Rich Failure" or "Post-cat
EGO Lean Failure" and the EGO Lazy fault will
be set for the appropriate sensor, respectively.
The engine will return to idle upon completion or
abortion of the of the closed-loop diagnostic test.
NOTE
• Be sure to check CL Test State, CL pre-cat test
status, and CL post-cat test status to determine
if the test was successful. If the test failed for
ANY reason, faults will be displayed and
configured system alarm(s) (soft warning, hard
warning, or MIL) will be generated. Technicians
should clear
Closed-Loop Test.
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ECM SYSTEM
faults after running
(To be continued)
KiSC issued 12, 2016 A
the