Inspection Procedure

HINT:

Start the inspection from step 1 when using the hand-held tester and start from step 3 when not using the hand-held tester.

READ VALUE OF HAND-HELD TESTER (FRONT SPEED SENSOR)
1. Connect the hand-held tester to the DLC3.
2. Start the engine.
3. Select the DATA LIST mode on the hand-held tester.
4. 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.
  
  Fig 1: Checking Difference Between Speed Value Output
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
  
  OK: There is almost no difference from the displayed speed value.
  
  HINT:
  
  There is tolerance of +/- 10 % in the speedometer indication.
1. NG: Go to step 3 .
2. OK: GO TO NEXT STEP.
INSPECT SPEED SENSOR AND SENSOR ROTOR SERRATIONS
INSPECTION USING OSCILLOSCOPE
1. Connect the oscilloscope to terminal FR+ - FR- or FL+ - FL- of the skid control ECU.
2. Drive the vehicle at about 19 mph (30 km/h), and check the signal waveform.
OK: A waveform as shown in a figure should be output.

HINT:
- As the vehicle speed (wheel revolution speed) 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 it.
  
  Fig 2: Inspecting Oscilloscope
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: Go to step 6 .
2. OK: REPLACE ABS & TRACTION ACTUATOR ASSY (See REPLACEMENT )

INSPECT FRONT SPEED SENSOR

Make sure that there is no looseness at the connectors' locking part and connecting part of connector.
Disconnect the speed sensor connector.

Measure the resistance according to the value (s) in the table below.

Standard:

LH:

SPECIFICATION TESTER CONNECTION

Tester Connection	Specified Condition
A4-1 (FL+) - A4-2 (FL-)	0.6 to 2.5 kΩ

Fig 3: Inspecting Front Speed Sensor

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

RH:

SPECIFICATION TESTER CONNECTION

Tester Connection	Specified Condition
A5-1 (FR+) - A5-2 (FR-)	0.6 to 2.5 kΩ

Measure the resistance according to the value (s) in the table below.

Standard:

LH:

SPECIFICATION TESTER CONNECTION

Tester Connection	Specified Condition
A4-1 (FL+) - Body ground	10 kΩ or higher
A4-2 (FL-) - Body ground	10 kΩ or higher

RH:

SPECIFICATION TESTER CONNECTION

Tester Connection	Specified Condition
A5-1 (FR+) - Body ground	10 kΩ or higher
A5-2 (FR-) - Body ground	10 kΩ or higher

NOTE: Check the speed sensor signal after replacement (see PRE-CHECK ).

NG: REPLACE FRONT SPEED SENSOR (See REPLACEMENT )
OK: GO TO NEXT STEP.

CHECK HARNESS AND CONNECTOR (FRONT SPEED SENSOR - SKID CONTROL ECU)

Disconnect the skid control ECU connector and the front speed sensor connector.

Measure the resistance according to the value (s) in the table below.

Standard:

LH:

SPECIFICATION TESTER CONNECTION

Tester Connection	Specified Condition
S27-18 (FL+) - A4-1 (FL+)	Below 1 Ω
S27-4 (FL-) - A4-2 (FL-)	Below 1 Ω

RH:

SPECIFICATION TESTER CONNECTION

Tester Connection	Specified Condition
S27-3 (FR+) - A5-1 (FR+)	Below 1 Ω
S27-17 (FR-) - A5-2 (FR-)	Below 1 Ω

Measure the resistance according to the value (s) in the table below.

Fig 4: Checking Harness And Connector (Front Speed Sensor - Skid Control ECU)

Standard:

LH:

SPECIFICATION TESTER CONNECTION

Tester Connection	Specified Condition
S27-18 (FL+) - Body ground	10 kΩ or higher
S27-14 (FL-) - Body ground	10 kΩ or higher

RH:

SPECIFICATION TESTER CONNECTION

Tester Connection	Specified Condition
S27-3 (FR+) - Body ground	10 kΩ or higher
S27-17 (FR-) - Body ground	10 kΩ or higher

NG: REPAIR OR REPLACE HARNESS OR CONNECTOR
OK: GO TO NEXT STEP.

INSPECT SPEED SENSOR AND SENSOR ROTOR SERRATIONS
INSPECTION USING OSCILLOSCOPE
1. Connect the oscilloscope to terminal FR+ - FR- or FL+ - FL- of the skid control ECU.
2. Drive the vehicle at about 19 mph (30 km/h), and check the signal waveform.
OK: A waveform as shown in a figure should be output.

HINT:
- As the vehicle speed (wheel revolution speed) increases, a cycle of the waveform narrows and the fluctuation in the output voltage becomes greater.
  
  Fig 5: Inspecting Speed Sensor And Sensor Rotor Serrations
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
- 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 it.
1. NG: Go to step 6
2. OK: REPLACE ABS & TRACTION ACTUATOR ASSY (See REPLACEMENT )
INSPECT 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.
    NOTE: Check the speed sensor signal after the replacement (see PRE-CHECK ).
    
    Fig 6: Inspecting Front Speed Sensor
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: REPLACE FRONT SPEED SENSOR (See REPLACEMENT )
2. OK: GO TO NEXT STEP.
INSPECT SPEED SENSOR TIP
1. Remove the front speed sensor (See REPLACEMENT ).
2. Check the sensor tip.
  OK: No scratches or foreign matter on the sensor tip.
  
  NOTE: Check the speed sensor signal after the replacement (see PRE-CHECK ).
1. NG: CLEAN OR REPAIR SPEED SENSOR
2. OK: GO TO NEXT STEP.
INSPECT SPEED SENSOR ROTOR
1. Remove the front speed sensor rotor.
2. Check the sensor rotor serrations.
  OK: No scratches, missing teeth or foreign matter on the rotors.
  
  HINT:
  
  If there is foreign matter in the rotor, remove it and check the output waveform after reassembly.
  
  NOTE: Check the speed sensor signal after the replacement (see PRE-CHECK ).
  
  Fig 7: Inspecting Speed Sensor Rotor
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: CLEAN OR REPAIR SPEED SENSOR ROTOR
2. OK: REPLACE ABS & TRACTION ACTUATOR ASSY (See REPLACEMENT )