TROUBLESHOOTING
Troubleshooting by DTC Fault Codes
12/05
6LY3 Service Manual
13-37
© 2007 Yanmar Marine International
P0120/0 (Main Throttle Position Sensor)
Fault Code
Fail Mode:
• The sub-throttle will be selectable with the
sub-throttle lamp blinking.
• Once sub-throttle is selected (activated), the
sub-throttle keeps working even if the main
throttle goes back to normal status.
• The marine gear transmission control (shift)
function is independent of the engine control,
which means the shifting function should be
controlled by the control head.
NOTICE: Activate the sub-throttle: Move the
sub-throttle to full counterclockwise and then back it
up slightly. Reset the sub-throttle fault code: Key
Off
.
See Rocker Switch Panel on page 12-23
.
DTC
P0120/0
Main Throttle Position Sensor
DTC / FMI
1. Condition, 2. Fault, 3. Time to Detect, 4. Display
Check Point
P0120/0
1. Key switch ON
2. Teleflex i2 module (i832X) sends a message that indicates throttle malfunction
status
3. —
4. MAIN THROTTLE, CHECK ENGINE on the TELEFLEX display
Main throttle head
Fail Mode
Target engine slows to low idle speed and stays there until the sub-throttle gets activated.
Sub-throttle is selectable when the sub-throttle lamp is blinking.
If the sub-throttle is selected, the lamp turns on.
Once the sub-throttle is selected, the sub-throttle keeps working even if the main throttle would
go back to normal.
Limited Operation
Yes
1. If the sub-throttle is selected: Sub-throttle is active.
2. If the sub-throttle is inactive: Engine speed is fixed at low idle or 1000 rpm
(Idle in Neutral and 1000 rpm in Forward / Reverse).
Fail Release
Yes
When ECU receives data of no error status from i2 module
Limited Operation Release
1. If the sub-throttle is active: No.
2. If the sub-throttle is inactive: Yes.
After the main throttle failure is cleared
Remarks
CAN communication error is stated as DTC U0146 “CAN communication gateway” not “Main
throttle position sensor.”
Limited Operation
—
Fail Release
Yes (i2 module communication error)
Remarks
This DTC comes from the communication between the i2 module and the ECU only. The TELEFLEX
control head malfunction will be detected as “Main Throttle Position Sensor Error.” The marine gear
transmission control (shift) function is independent of the throttle function. This means that shifting
function should be controlled as i2 module function. (If i2 module is not active, then U0146 occurs and
the shift function may become inactive.) Normal communication continues after receiving data from i2
module. If the sub-throttle is selected before communication gets back to normal, the main throttle will
stay inactive.
