Yanmar 3TNV82A Troubleshooting Manual page 203

Method and Procedure of Failure Diagnosis
Work Description
1. Check of the relay coil resistance value (relay only):
• Remove the E-ECU main relay from the harness.
• Check the continuity between relay side terminals A and B using a circuit tester.
NG
OK
2. Check of the relay coil resistance value (relay only):
• Remove the E-ECU main relay from the harness.
• Measure the resistance between relay side terminals C and D using a circuit tester.
Measurement conditions
Tester (+) side
Terminal C
Terminal D
Terminal C
Terminal D
*As a reverse-biased diode is integrated, the above-mentioned checking method is applied, and the measured value
varies depending on a circuit tester to be used.
NG
OK
3. Check of relay coil resistance value (relay + harness side):
• Install the E-ECU main relay to the harness.
• Remove E-ECU from the harness.
• Measure the resistance between battery cable (+) line and harness side E-ECU connector E34.
Measurement conditions
Tester (+) side
Battery (+) line
E34
Battery (+) line
E34
*As a reverse-biased diode is integrated, the above-mentioned checking method is applied, and the measured value
varies depending on a circuit tester to be used.
NG
OK
TNV DI Service Manual
Replace the E-ECU main relay.
Check the resistance of the E-ECU main relay coil. → Go to [2. Check of the relay
coil resistance value (relay only):]
Tester (-) side
Terminal D
Terminal C
Terminal D
Terminal C
Replace the E-ECU main relay.
Check the relay coil resistance with the E-ECU main relay and the harness being
connected. → Go to [3. Check of relay coil resistance value (relay + harness side):]
Tester (-) side
E34
Battery (+) line
E34
Battery (+) line
Replace the harness.
Check the harness for correct continuity. → Go to [4. Check of harness continuity:]
Measured value
Available (*)
OK when both are normal
Infinity (*)
NG: Fault of the relay internal
Infinity (*)
Measured value
Available (*)
OK: normal
Infinity (*)
Infinity (*) NG: Harness error
FAILURE DIAGNOSIS
Status
circuitry
Status
1-201