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:

    Checking the condition of the bulbs
    The following procedure applies to all of the bulbs. 1. Remove: Bulb WARNINGSince the headlight bulbs get extremely hot, keep flammable products and your hands away from them until they have cooled down. CAUTION: Be sure to hold the socket firmly when re ...

    Checking the piston pin
    1. Check: Piston pin Blue discoloration/grooves  Replace the piston pin and then check the lubrication system. 2. Measure: Piston pin outside diameter "a" Out of specification Replace the piston pin. 3. Measure: Piston pin bore diameter "b" Out of specifica ...

    Replacing an auxiliary light bulb
    This model is equipped with two auxiliary lights. If an auxiliary light bulb burns out, replace it as follows. Remove the socket (together with the bulb) by pulling it out. Auxiliary light bulb Remove the burnt out bulb by pulling it out. Insert a new bulb into t ...

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