Yanmar 3TNV82A Troubleshooting Manual page 178

FAILURE DIAGNOSIS
Work Description
1. Check of the relay coil resistance value (relay only):
• Remove the start assist relay from the harness.
• Measure the resistance between relay side terminals C and D using a circuit tester.
(REF) The resistance value of Yanmar standard start assist relay
Relay coil side C - D (40A relay)
Relay coil side C - D (70A relay)
Relay coil side C - D (90A relay)
NG
OK
2. Check of relay coil resistance value (relay + harness side):
• Install the start assist relay to the harness.
• Remove E-ECU from the harness.
• Measure the resistance between E-ECU connectors E44 and B00 using a circuit tester.
*See above-mentioned "(REF) Resistance of Yanmar standard start assist relay".
NG
OK
3. Check of harness continuity:
• Remove the start assist relay from the harness, and remove E-ECU from the harness.
• Check the harness continuity using a circuit tester.
Terminal
Relay coil (upstream side) E44
[Between E-ECU and sensor connector]
Relay coil (downstream side) B00
[Between E-ECU and sensor connector]
Between E33 and GND/E28/E45/E47
Between E44 and E43/E48
NG
OK
1-176
Terminal
Replace the start assist relay.
Check the relay coil resistance with the start assist relay and the harness being
connected. → Go to [2. Check of relay coil resistance value (relay + harness side):]
Check the harness for correct continuity. → Go to [3. Check of harness continuity:]
Check the movement of the start assist relay by a diagnosis tool. → Go to [4.
Movement check of the relay:]
• Check if the harness is damaged, or if the wiring is correct.
• Replace the harness.
Check the movement of the rack actuator relay by the diagnosis tool. → Go to [4.
Movement check of the relay:]
Method and Procedure of Failure Diagnosis
103Ω ± 10% (at 20°C)
103Ω ± 10% (at 20°C)
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
Unavailable OK: normal
NG: Harness short-circuited with power
Available
supply
TNV DI Service Manual
Specification
80Ω (at 20°C)
Status