Inspection Procedure

HINT:

Start the inspection from step 1 in case of using the hand-held tester and start from step 2 in case of not using the hand-held tester.

1. READ VALUE OF HAND-HELD TESTER (SPEED SENSOR OUTPUT VALUE) 
   1. Select the item "WHEEL SPEED FL (FR)" in the DATA LIST and read its value displayed on the hand-held tester.
   2. Check that there is no difference between the speed value output from the speed sensor displayed on the hand-held tester and the speed value displayed on the speedometer when driving the vehicle.

      OK: There is almost no difference from the displayed speed value. 

   HINT:

   There is tolerance of +/- 10 % in the speedometer indication.

   1. OK: CHECK AND REPLACE BRAKE ACTUATOR ASSY (SEE  REPLACEMENT  ) 

   NG: Go to Next Step. 

2. INSPECT FRONT SPEED SENSOR 
   1. Remove the front fender liner.
   2. Make sure that there is no looseness at the locking part and connecting part of the connector.
   3. Disconnect the speed sensor connector.
   4. Measure the resistance between terminals 1 and 2 of the speed sensor connector.

      Standard: 0.6 to 2.5 kΩ 

   5. Measure the resistance between terminals 1 and 2 of the speed sensor connector and body ground.

      Standard: 10 kΩ or higher 

      Fig 1: Measuring Front Speed Sensor Terminals Resistance

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
      SPEED SENSOR INSPECTION
      
      

      A	OK
      B	NG (Right front speed sensor)
      C	NG (Left front speed sensor)

   1. B: REPLACE SPEED SENSOR FRONT RH 
   2. C: REPLACE SPEED SENSOR FRONT LH 
   NOTE: Check the speed sensor signal after replacement (see TEST MODE PROCEDURE  ).

   A: Go to Next Step. 

3. CHECK HARNESS AND CONNECTOR (SPEED SENSOR - SKID CONTROL ECU ASSY) (SEE  ELECTRONIC CIRCUIT INSPECTION PROCEDURE  ) 
   1. NG: REPAIR OR REPLACE HARNESS AND CONNECTOR 

   OK: Go to Next Step. 

4. CHECK SPEED SENSOR AND SENSOR ROTOR SERRATIONS 

   (REFERENCE) INSPECTION USING OSCILLOSCOPE 

   1. Connect the oscilloscope to terminals FR+ - FR-, FL+ - FL- of the skid control ECU.
   2. Drive the vehicle at about 12 mph (20 km/h) and check the signal waveform.

      OK: A waveform as shown in the figure should be output. 

      Fig 2: Normal Signal Waveform

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   HINT:

   • As the vehicle speed (rpm of the wheels) increases, a cycle of the waveform narrows and the fluctuation in the output voltage becomes greater.
   • When noise is identified in the waveform on the oscilloscope, error signals are generated due to the speed sensor rotor's scratches, looseness or foreign matter attached to on it.
   1. OK: CHECK AND REPLACE BRAKE ACTUATOR ASSY (SEE  REPLACEMENT  ) 

   NG: Go to Next Step. 

5. CHECK FRONT SPEED SENSOR INSTALLATION 
   1. Check the speed sensor installation.

      OK: 

      • The installation bolt is tightened properly. Torque: 8.0 N.m (82 kgf.cm, 71 in.lbf) 
      • There is no clearance between the sensor and the front steering knuckle. 
        Fig 3: Checking Front Speed Sensor Installation

        Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
        SPEED SENSOR INSPECTION
        
        

        A	OK
        B	NG (Right front speed sensor)
        C	NG (Left front speed sensor)

   1. B: REPLACE SPEED SENSOR FRONT RH 
   2. C: REPLACE SPEED SENSOR FRONT LH 
      NOTE: Check the speed sensor signal after replacement (see TEST MODE PROCEDURE  ).

   A: Go to Next Step. 

6. CHECK SPEED SENSOR ROTOR AND SENSOR TIP 
   1. NG: CLEAN OR REPLACE SPEED SENSOR AND SENSOR ROTOR SERRATIONS 
      NOTE: Check the speed sensor signal after replacement (see TEST MODE PROCEDURE  ).

   OK: CHECK AND REPLACE BRAKE ACTUATOR ASSY (SEE  REPLACEMENT  )