2012 kx250f removing vehicle down sensor

Just wondering if any one knew how to remove the vehicle down sensor from a kx250f 2011-2013

its a small sensor bellow the fuel tank has three wires, im guesing that the ecu has to see a certain resistance/voltage to function once the bike is dropped it doesnt and cuts the bike

it must be possible you dont see the pros bikes cutting out when they flip them...?

any suggestions would be great thanks

The manual mentions that if the sensor is faulty the bike will cut out after 3 seconds if not then 30 seconds.


30 seconds is a long time, so its plenty time to pick the bike up.


Ive never tested how long it takes.  

yerp i understand what it does, just dont feel like paying $120 to replace my faulty one

Does anyone have a picture of the wiring diagram and any specs given to test the sensor? I would think it could be bypassed, just a matter of determining what sends out in the upright position.

I have the workshop manual will see if I can post the diagram

it couldnt be too hard, after all blokes do back flip them and dont have them cut out.

im guessing that the sensor has a particular resistance, and if this increases or descreases the voltage back to the ecu would change thus cutting out the bike...

so im hoping with a multimeter i could test to determine what this resistance is whilst the sensor is up right, then go and buy a resistor of the same value and install it on the bike.( remove the guts of the old sensor and just solder in the resistor) but atm this is just an idea and could be totally wrong.

i do have access to another kx250f to determine what this value should be.

From the manual - Hope it Helps 


Vehicle-down Sensor (Service Code 31)
When themotorcycle is down, the engine stops according
to the condition of the below table.
Engine Speed Time Engine Condition
2 500 rpm or less After 30 seconds Stop
2 500 rpm or more After 3 seconds Stop
When the vehicle-down sensor is broken, the engine will
stop at 3 seconds after the engine starts.
Vehicle-down Sensor Removal
Never drop the vehicle-down sensor, especially on
a hard surface. Such a shock to the sensor can
damage it.
• Remove the fuel tank (see Fuel Tank Removal).
• Pull the vehicle-down sensor [A] from the bracket.
• Disconnect the connector .
Vehicle-down Sensor Installation
• The UPPER mark [A] of the sensor should face upward
and install the sensor.
• Connect the connector.
Incorrect installation of the vehicle-down sensor
could cause sudden loss of engine power. The
rider could lose balance during certain riding situations
like leaning over in a turn with the potential
for an accident resulting in injury or death. Ensure
that the vehicle-down sensor is held in place by the
sensor bracket.
Vehicle-down Sensor Input Voltage Inspection
○Be sure the battery is fully charged.
• Disconnect the vehicle-down sensor connector and connect
the measuring adapter [A] between these connectors.
Main Harness
Vehicle-down Sensor [C]
Special Tool - Measuring Adapter: 57001-1700
• Connect a digital meter [D] to the measuring adapter
Vehicle-down Sensor Input Voltage
Connections to Adapter:
Digital Meter (+) → R (sensor R/Y) lead
Digital Meter (–) → BK (sensor GY) lead
• Refer to the Self-diagnosis Procedures, connect the 12 V
battery to the main harness.
•Measure the input voltage with the engine stopped and
with the connector joined.
Input Voltage
Standard: DC 4.75 ∼ 5.25 V
If the reading is within the standard, check the output voltage
(see Vehicle-down Sensor Output Voltage Inspection).
If the reading is out of the standard, remove the ECU and
check the wiring for continuity between the main harness
Special Tool - Hand Tester: 57001-1394
○Disconnect the ECU and sensor connectors.
Wiring Continuity Inspection
ECU Connector [A] ←→
Vehicle-down Sensor Connector
R/Y lead [C] (ECU terminal 12)
GY lead [D] (ECU terminal 17)
If the wiring is good, check the ECU for its ground and
power supply (see ECU Power Supply Inspection).
If the ground and power supply are good, replace the ECU
(see ECU Removal/Installation).
Vehicle-down Sensor Output Voltage Inspection
•Remove the vehicle-down sensor, and connect the measuring
adapter [A].
Special Tool - Measuring Adapter: 57001-1700
Main Harness
Vehicle-down Sensor [C]
•Connect a digital meter [D] to the measuring adapter
Vehicle-down Sensor Output Voltage
Connections to Adapter:
Digital Meter (+) → W (sensor BR) lead
Digital Meter (–) → BK (sensor GY) lead

Tried to PM you.  I have two of them collecting dust.  You let me know if you want one.  I think it's good to have for safety as well as engine protection . . . just saying.  There is a reason for that little box.

My buddies bike starts then shuts off.. I wonder if its because of this sensor

a easy way to test it is just swap with a friends bike

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