Main Relay - Yanmar 3TNV82A Troubleshooting Manual

Method and Procedure of Failure Diagnosis

Main relay

Related DTC
DTC P0686/4
Work flow
*For details of the work, see after-mentioned "<Work Description>."For the operation of the
diagnosis tool, see "Diagnosis tool Operation Manual" separately.
Initial diagnosis with the diagnosis tool
A. Check the current
failure display
Current failure
exists.
Key switch OFF.
B. Log into the diagnosis tool.
Failure diagnosis flow
1. Check of relay
contact continuity
OK
2. Check of
relay coil resistance
(relay only)
OK
3. Check of
relay coil resistance
(relay + harness)
NG
Replace the
harness.
TNV DI Service Manual
Main relay error
DTC in the failure history indication
[Check items]: Logging into the diagnosis tool
• Cannot log in
• Can log in
NG
NG
OK
4. Check the harness
continuity.
FAILURE DIAGNOSIS
Check the failure
conditions.
→ Normal
→ Main relay contact stuck?
Main relay coil downstream
short-circuited with GND?
Replace the relay.
Replace the relay.
NG
Replace the
harness.
OK
Replace the
E-ECU.
017558-00E
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