Yanmar 6LY3 series Service Manual page 303

Troubleshooting by Symptom
12/05
Trouble symptom
The engine cannot be
controlled. Engine speed does
not increase.
The engine cannot be
controlled. Engine speed is not
reduced.
The engine cannot be
controlled.
The gearbox cannot be
engaged or disengaged.
The engine cannot be
controlled. The shift position
cannot be changed.
6LY3 Service Manual
Causes
Engine is overloaded.
CAN communication error or
main throttle error detected.
(Main throttle cannot be
activated.)
Faulty control head. (Main
throttle can be activated.)
Sub-throttle or wire harness
failed (in operation by
sub-throttle).
Faulty control head. (Main
throttle can be activated.)
Sub-throttle or wire harness
failed. (In operation by
sub-throttle.)
Error of rack position sensor:
Detected error (P1201).
Fuel injection pump rack is
stuck.
The gearbox connector is
disconnected.
Faulty contact of the gearbox
connector.
Open circuit in the gearbox
harness.
Faulty electromagnetic valve
on the gearbox.
Low gearbox oil.
Faulty gearbox hydraulic oil
pump.
Worn clutch friction discs.
Seized clutch friction discs.
© 2007 Yanmar Marine International
Corrective action
Check around the propeller
and the boat hull.
Check the input value of the
acceleration sensor with a
YDT. If an error is detected,
correct or replace the harness.
If error is not detected and a
malfunction is found, replace
the control head.
Check the input value of
acceleration sensor with a
YDT. If an error is not detected,
check the signal voltage of the
sub-throttle sensor. If failure is
found, correct or replace the
wire harness or sub-throttle
sensor.
Check the input value of the
acceleration sensor with a
YDT. If an error is not detected
and a malfunction is found,
replace the control head.
Check the input value of the
acceleration sensor with a
YDT. If an error is not detected,
check the signal voltage of the
sub-throttle sensor. If failure is
found, correct or replace the
wire harness or sub-throttle
sensor.
Check the rack log with a YDT.
If a malfunction is found,
replace the fuel injection pump.
Wire according to the manual.
Check the connector terminal.
Repair if necessary.
Check the harness.
Replace the electromagnetic
valve.
Check the oil level. If low, refill. Refer to the Gearbox Manual.
Disassemble and check.
Replace if necessary.
Disassemble and check.
Replace if necessary.
Disassemble and check.
Replace if necessary.
TROUBLESHOOTING
Remarks
—
Refer to the YDT Manual. If a
main throttle error is detected,
engine speed goes to idle.
Refer to the YDT Manual.
Refer to Figure 13-1 on
page 13-14.
Refer to the YDT Manual.
If a main throttle error is
detected, engine speed goes
to idle.
Refer to the YDT Manual.
Refer to Figure 13-1 on
page 13-14.
DTC: See Troubleshooting by
DTC Fault Codes on
page 13-28.
Refer to the YDT Manual.
See Alternator Wiring Diagram
on page 11-8.
See Alternator Wiring Diagram
on page 11-8.
See Alternator Wiring Diagram
on page 11-8.
Refer to the Gearbox Manual.
Refer to the Gearbox Manual.
Refer to the Gearbox Manual.
Refer to the Gearbox Manual.
13-13