Yanmar 3TNV82A Troubleshooting Manual page 197

Method and Procedure of Failure Diagnosis
Work Description
1. Check of the rack actuator coil resistance (actuator only):
• Remove the harness from the rack actuator.
• Measure the resistance between rack actuator terminals A and B using a circuit tester.
(REF) Coil resistance value of Yanmar standard rack actuator
NG
OK
2. Check of the rack actuator coil resistance (harness + actuator):
• Connect rack actuator and harness, and remove E-ECU and rack actuator from the harness.
• Measure the resistance between harness side E-ECU connector terminal E42 and rack actuator relay
contact downstream side E18 using a circuit tester.
*See above-mentioned "(REF) Coil resistance of Yanmar standard speed sensors".
NG
OK
3. Check of harness continuity:
• Remove the rack actuator and E-ECU from the harness.
• Check the harness continuity using a circuit tester.
Terminal
Actuator coil wire (downstream side) E42
[Between E-ECU and sensor connector]
Between actuator coil (upstream) and
rack actuator relay contact (downstream)
Between rack actuator relay contact
(downstream) and main relay contact
(downstream)
NG
OK
TNV DI Service Manual
Terminal
Coils A - B
Replace the fuel injection pump.
Check the resistance between actuator terminals A and B with the rack actuator and
the harness being connected. → Go to [2. Check of the rack actuator coil resistance
(harness + actuator):]
Check the harness for correct continuity. → Go to [3. Check of harness continuity:]
Check the movement of the actuator by the diagnosis tool. → Go to [4. Movement
check of the rack actuator:]
• Check if the harness is damaged, or if the wiring is correct.
• Replace the harness.
Replace the E-ECU.
Continuity
Available OK: normal
Unavailable NG: harness disconnection
Available OK: normal
Unavailable NG: harness disconnection
Available OK: normal
Unavailable NG: harness disconnection
FAILURE DIAGNOSIS
Specification
1Ω ± 10%
Status
1-195