FAILURE DIAGNOSIS
1-176
TNV DI Service Manual
Method and Procedure of 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
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”.
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
Specification
Relay coil side C - D (40A relay)
Relay coil side C - D (70A relay)
Relay coil side C - D (90A relay)
103
Ω
± 10% (at 20°C)
103
Ω
± 10% (at 20°C)
80
Ω
(at 20°C)
NG
Replace the start assist relay.
OK
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):]
NG
Check the harness for correct continuity.
→
Go to [3. Check of harness continuity:]
OK
Check the movement of the start assist relay by a diagnosis tool.
→
Go to [4.
Movement check of the relay:]
Terminal
Continuity
Status
Relay coil (upstream side) E44
[Between E-ECU and sensor connector]
Available
OK: normal
Unavailable
NG: harness disconnection
Relay coil (downstream side) B00
[Between E-ECU and sensor connector]
Available
OK: normal
Unavailable
NG: harness disconnection
Between E33 and GND/E28/E45/E47
Unavailable
OK: normal
Available
NG: harness short-circuited with GND
Between E44 and E43/E48
Unavailable
OK: normal
Available
NG: Harness short-circuited with power
supply
NG
• Check if the harness is damaged, or if the wiring is correct.
• Replace the harness.
OK
Check the movement of the rack actuator relay by the diagnosis tool.
→
Go to [4.
Movement check of the relay:]
TNV_DI_SM_A4-Troubleshooting.book 176 ページ 2007年11月15日 木曜日 午後5時27分