Yanmar 3TNV82A Troubleshooting Manual page 187

Method and Procedure of Failure Diagnosis
Work Description
1. Check of the EGR step motor coil resistance (EGR only):
• Remove the EGR valve from the harness.
• Measure the resistance between EGR side coil terminals 4-5, (1-2, 5-6, 2-3) using a circuit tester.
(REF) Resistance value of Yanmar standard EGR step motor coil
Coil terminal 4 - 5 (A-Phase)
Coil terminal 1 - 2 (B-Phase)
Coil terminal 5 - 6 (C-Phase)
Coil terminal 2 - 3 (D-Phase)
NG
OK
2. Check of EGR step motor coil resistance (relay + harness side):
• Install the EGR valve to the harness.
• Remove E-ECU from the harness.
• Measure the coil resistance at the E-ECU connector using a circuit tester.
*See above-mentioned "(REF) Resistance of Yanmar standard EGR step motor coil".
NG
OK
TNV DI Service Manual
Terminal
Replace the EGR valve.
Check the EGR step motor coil resistance with the EGR valve and the harness
being connected. → Go to [2. Check of EGR step motor coil resistance (relay +
harness side):]
Step motor
A-Phase
B-Phase
C-Phase
D-Phase
Check the harness for correct continuity. → Go to [3. Check of harness continuity:]
Check the movement of the EGR by the diagnosis tool. → Go to [4. Movement check
of the EGR:]
FAILURE DIAGNOSIS
Specification
15 ± 2Ω
ECU connector terminal number
E31-E48
E21-E48
E11-E48
E01-E48
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