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:

    Troubleshooting method
    The engine operation is not normal and the engine trouble warning light comes on. 1. Check: Fault code number a. Check the fault code number displayed on the FI diagnostic tool. b. Identify the faulty system with the fault code. Refer to "Self-Diagnostic Function table". c. Identi ...

    Checking and lubricating the cables
    The operation of all control cables and the condition of the cables should be checked before each ride, and the cables and cable ends should be lubricated if necessary. If a cable is damaged or does not move smoothly, have a Yamaha dealer check or replace it. WARNING! Damage to the out ...

    Owner's tool kit
    Owner's tool kit Owner's tool kit Engine oil drain attachment The owner's tool kit is located under the rider seat. The service information included in this manual and the tools provided in the owner's tool kit are intended to assist you in the performance of preventive maint ...

    2020 Copyright www.yam-r125.net |