Yanmar 3TNV82A Troubleshooting Manual page 156

FAILURE DIAGNOSIS
ECU Temperature Sensor
Related DTC
P0668/4
DTC P0669/3
P1644/2
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.
B. Check the detected
value to estimate the
cause of failure.
Failure diagnosis flow
Repeat
1. Do the same steps as
1-154
Failure with ECU Temperature Sensor (Low Voltage)
Failure with ECU Temperature Sensor (High Voltage)
Intermittent Failure WITH ECU Temperature Sensor
DTC in the failure history indication
Turn ON/OFF
the key switch.
in the initial diagnosis
above.
OK
Replace the
E-ECU.
Method and Procedure of Failure Diagnosis
[Check items]: ECU temperature
ECU temperature is stationary at 30°C
ECU temperature equivalent to
ambient temperature
DTC in the failure history indication
Check the failure
conditions.
ECU may be faulty.
Normal
Check the failure
conditions.
TNV DI Service Manual
017538-00E