Yamaha YZF-R125 Service Manual: Throttle position sensor

1. Check:

  • Throttle position sensor

a. Connect the digital circuit tester to the terminals of the throttle body sensor assembly coupler as shown.


  • Positive tester probe → gray/red terminal "1"
  • Negative tester probe → gray/black terminal "2"

b. Measure the throttle position sensor input voltage.

Out of specification → Replace or repair the wire harness.


c. Connect the digital circuit tester to the terminals of the throttle body sensor assembly coupler as shown.

  • Positive tester probe → yellow terminal "3"
  • Negative tester probe → gray/black terminal "2"

d. While slowly opening the throttle, check that the throttle position sensor output voltage is increased.

Voltage does not change or it changes abruptly → Replace the throttle body.

Out of specification (closed position) → Replace the throttle body.


Throttle position sensor


    Checking the throttle body sensor assembly
    WARNING Do not remove the throttle body sensor assembly. Handle the throttle body sensor assembly with special care Never subject the throttle body sensor assembly to strong ...

    Intake air pressure sensor
    1. Check: Intake air pressure sensor output voltage Out of specification Replace the throttle body. a. Connect the pocket tester (DC 20 V) to the throttle body sensor assembly coupler as ...

    Other materials:

    Removing the rear brake caliper
    NOTE: Before disassembling the brake caliper, drain the brake fluid from the entire brake system. 1. Remove: Union bolt "1" Copper washers "2" Brake hose "3" NOTE: Put the end of the brake hose into a container and pump out the brake fluid carefully. ...

    Adjusting the rear disc brake
    1. Check: Brake pedal position (distance "a" from the center of the rider footrest to the center of the brake pedal) Out of specification Adjust. 2. Adjust: Brake pedal position a. Loosen the locknut "1". b. Remove the cotter pin "2", washer "3", and pin "4". c. Turn t ...

    Lubricating the drive chain
    The drive chain consists of many interacting parts. If the drive chain is not maintained properly, it will wear out quickly. Therefore, the drive chain should be serviced, especially when the vehicle is used in dusty areas. This vehicle has a drive chain with small rubber O-rings between eac ...

    2023 Copyright www.yam-r125.net |