Yanmar 3TNV82A Troubleshooting Manual page 161

Method and Procedure of Failure Diagnosis
3. Check of harness continuity:
• Remove the cooling water temperature sensor and E-ECU from the harness.
• Check the harness continuity using a circuit tester.
Terminal
Sensor signal wire E16 (E25)
[E-ECU ñ between sensor connector]
Sensor GND wire E28
[Between E-ECU and sensor connector]
Between E16 and other terminal/GND
(between E25 and other terminal/GND)
E28 ñ GND/E45/E47
Between E28 and other terminals
NG
OK
4. Output voltage check of the cooling water temperature sensor:
• Connect the 2G eco-checker harness between E-ECU and machine's harness (for details, see[How to
use the 2G eco-checker harness] (P.1-135). And connect the all connectors (sensors, E-ECU).
• Measure the voltage between sensor signal E16 and E28 (E35 and E28) using a circuit tester.
Voltage
E16(E25) ≤ 0.2[V]
0.2[V] < E16(E25) < 4.8V
4.8V ≤ E16(E25)
NG
OK
TNV DI Service Manual
• Check if the harness is damaged, or if the wiring is correct.
• Replace the harness.
Check the output voltage of the cooling water temperature sensor. → Go to [4.
Output voltage check of the cooling water temperature sensor:]
Status
NG
OK
(Normal range)
NG
• Check if the harness is damaged, or if the wiring is correct.
• Replace the harness.
ReplaceE-ECU.
Continuity
Available OK: normal
Unavailable NG: harness disconnection
Available OK: normal
Unavailable NG: harness disconnection
Unavailable OK: normal
Available NG: harness short-circuited with GND
Available OK: normal
Unavailable NG: harness disconnection
Unavailable OK: normal
Available NG: harness short-circuited with another
wiring
• Replace the harness.
• Replace the cooling water temperature sensor.
ReplaceE-ECU.
• Replace the harness.
• Replace the cooling water temperature sensor.
FAILURE DIAGNOSIS
Status
Action
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