Yamaha YZF-R125 Service Manual: 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 shown.


  • Positive tester probe
    pink/white "1"
  • Negative tester probe
    gray/black "2"

Intake air pressure sensor


b. Set the main switch to "ON".

c. Measure the intake air pressure sensor output voltage.

    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 t ...

    Intake air temperature sensor
    1. Check: Intake air temperature sensor resistance Out of specification Replace the throttle body. a. Connect the pocket tester ( × 1k) to the throttle body sensor assembly co ...

    Other materials:

    Cable routing
    Front brake light switch lead Right handlebar switch lead Throttle cable Main switch Clutch cable Clutch switch lead Left handlebar switch lead Sub-wire harness Horn Speed sensor lead Front brake hose Main switch lead Left headlight assembly lead Right headlight asse ...

    Checking the radiator fan motor
    1. Check: Radiator fan motor Faulty/rough movement → Replace. a. Disconnect the radiator fan motor coupler from the wire harness. b. Connect the battery (DC 12 V) as shown. Positive tester probe → blue "1" Negative tester probe → black "2" c. Measure ...

    Chassis tightening torques
    NOTE: First, tighten the lower ring nut to approximately 48 Nm (4.8 m.kg, 35 ft.lb) with a torque wrench, then loosen the lower ring nut completely. Retighten the lower ring nut to 13 Nm (1.3 m.kg, 9.4 ft.lb) with a torque wrench. ...

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