AUTO-TENSIONER CHECK


OPERATION CHECK
1.Turn OFF the engine from the idle state then check to see that the drive belt is not protruding from the pulley width of the auto tensioner.
2.Remove the drive belt (Refer to ).

3.Install the tool to the auto tensioner, and check that no binding is present by turning the auto tensioner in the left and right directions.
4.If there are any problems in the procedure 1 or 3, replace the auto tensioner (Refer to ).
5.Install the drive belt (Refer to ).

FUNCTION CHECK
You can verify if the auto tensioner is defective or not by checking the drive belt tension.

When the vibration frequency is measured {Special tool (MB992080) is used}: Recommendation
note The vibration frequency measuring method is recommended for check and adjustment of the drive belt tension.
1.Check the drive belt tension (Refer to ).


2.Measure the drive belt tension vibration frequency by the following procedures:
(1) Connect the Special tool microphone assembly (MB992082) to the Special tool belt tension meter (MB992081) of the Special tool belt tension meter set (MB992080).
(2) Press the "POWER" button to turn on the power supply.
(3) Press the numeral key of "1" and check that "No.1" appears on the upper left of the display.
note This operation is to temporarily set the preset data such as the belt specifications, because if the measurement is taken without input of the belt specifications, conversion to tension value (N) cannot be made, resulting in judgement of error.
(4) Press "Hz" button twice to change the display to the frequency display (Hz).
(5)
caution
  • The temperature of the surface of the belt should be as close to normal temperature as possible.
  • Do not allow any contaminants such as water or oil to get onto the microphone.
  • If strong gusts of wind blow against the microphone or if there are any loud sources of noise nearby, the values measured by the microphone may not correspond to actual values.
  • If the microphone is touching the belt while the measurement is being made, the values measured by the microphone may not correspond to actual values.
  • Do not take the measurement while the vehicle’s engine is running.
Hold special tool (MB992080) to the middle of the drive belt between the pulleys (at the place indicated by arrow), approximately 10 - 15 mm away from the rear surface of the belt so that it is perpendicular to the belt (within an angle of ± 15 degree).
(6) Press the "MEASURE" button.
(7) Gently tap the middle of the belt between the pulleys (the place indicated by the arrow) with your finger as shown in the illustration, and measure that the vibration frequency of the belt is within the standard value.
Standard value: 107 - 151 Hz
note To take the measurement repeatedly, fillip the belt again.
(8) After the completion of the measurement, press and hold the "POWER" button to turn off the power supply.
3.If not within the standard value, replace the auto tensioner (Refer to ).

When the vibration frequency is measured V.C.I. is used: Recommendation
note The vibration frequency measuring method is recommended for check and adjustment of the drive belt tension.
1.Check the drive belt tension (Refer to ).



2.Measure the drive belt tension vibration frequency by the following procedures:
(1)
caution To prevent damage to special tool V.C.I. (MB991824), always turn the ignition switch to the "LOCK" (OFF) position before connecting or disconnecting special tool V.C.I. (MB991824).
Connect special tool belt tension meter set (MB991668) to special tool V.C.I. (MB991824).
(2) Connect special tool M.U.T.-III main harness A (MB991910) to special tool V.C.I. (MB991824).
(3) Connect special tool M.U.T.-III main harness A (MB991910) to the diagnosis connector.
(4) Turn the ignition switch to "ON" position, and select "Belt Tension" on the menu screen.
(5)
caution
  • The temperature of the surface of the belt should be as close to normal temperature as possible.
  • Do not allow any contaminants such as water or oil to get onto the microphone.
  • If strong gusts of wind blow against the microphone or if there are any loud sources of noise nearby, the values measured by the microphone may not correspond to actual values.
  • If the microphone is touching the belt while the measurement is being made, the values measured by the microphone may not correspond to actual values.
  • Do not take the measurement while the vehicle’s engine is running.
Hold special tool belt tension meter set (MB991668) to the middle of the drive belt between the pulleys (at the place indicated by arrow), approximately 10 - 20 mm away from the rear surface of the belt so that it is perpendicular to the belt (within an angle of ± 15 degree).
(6) Gently tap the middle of the belt between the pulleys (the place indicated by the arrow) with your finger as shown in the illustration, and measure that the vibration frequency of the belt is within the standard value.
Standard value: 107 - 151 Hz
3.If not within the standard value, replace the auto tensioner (Refer to ).

When using the tension gauge
1.Check the drive belt tension (Refer to ).

2.Use a belt tension gauge in the middle of the belt between the pulleys (at the place indicated by the arrow) to measure that the belt tension is within the standard value.
Standard value: 196 - 392 N
3.If not within the standard value, replace the auto tensioner (Refer to ).