FAILURE DIAGNOSIS
TNV DI Service Manual
1-185
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
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”.
Terminal
Specification
Coil terminal 4 - 5 (A-Phase)
Coil terminal 1 - 2 (B-Phase)
Coil terminal 5 - 6 (C-Phase)
Coil terminal 2 - 3 (D-Phase)
15 ± 2
Ω
NG
Replace the EGR valve.
OK
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
ECU connector terminal number
A-Phase
B-Phase
C-Phase
D-Phase
E31-E48
E21-E48
E11-E48
E01-E48
NG
Check the harness for correct continuity.
→
Go to [3. Check of harness continuity:]
OK
Check the movement of the EGR by the diagnosis tool.
→
TNV_DI_SM_A4-Troubleshooting.book 185 ページ 2007年11月15日 木曜日 午後5時27分