Yanmar 6LY3 series Service Manual page 333

Troubleshooting by DTC Fault Codes
12/05
Terminals
[ECU_G_S] - other terminal, ECU Pin #35
1. Check the wire harness.
Failure
2. Replace the wire harness.
OK Check the sensor voltage output (see the following).
4. Sensor output voltage
Check for open / short circuit.
Make sure all connectors (Sensor and ECU) are connected.
Measure the voltage between the sensor signal and ground ([ECU_TH] - [ECU_G_S]).
Voltage
[ECU_TH]
≤ 0.2V
0.2V <
[ECU_TH]
< 4.8V
[ECU_TH]
≥ 4.8V
Failure 1. Check the wire harness.
2. Replace the wire harness.
OK Replace the ECU.
Case 2: When the DTC is not active (logged
status), the ECU stores the past DTC information
and the YDT indicates a logged DTC. If a connector
comes loose, it may be the reason for a logged
DTC.
Checking the wire harness:
Check the wire harness between the sensor and
the ECU. See if the alarm turns on or not.
Recommendation: Before starting this, it may be
easier to clear DTC information by the YDT,
because the counter goes to 0 and can easily
identify when an alarm has occurred.
DTC
Yes Check the connector terminal. Replace the wire
harness.
No No action
6LY3 Service Manual
Status
Defective
Normal
condition
Defective
Contents
© 2007 Yanmar Marine International
Continuity
Defective OK: Normal
Good
Failure: Open circuit
1. Replace the wire harness.
Wire harness [ECU_TH] short to ground / ground
2. Replace the temperature sensor.
Sensor failure
Replace the ECU if DTC is still active.
(See Sensor Specification Chart on page 13-34.)
1. Replace the wire harness.
Wire harness [ECU_TH] short to ground
2. Replace the temperature sensor.
Sensor failure
Figure 13-18
ECU
1 – Breakout box is a branch harness and
connector from each pin of ECU. The tester
probe can be inserted here, and the voltage
and the waveform between each ECU pin
can be measured.
2 – Breakout Box and Harness
3 – Engine Harness
TROUBLESHOOTING
Status
Action
(1)
(2)
(3)
0006149
Figure 13-18
13-43