Inspection Procedure

HINT:

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

READ VALUE OF HAND-HELD TESTER (FRONT SPEED SENSOR)

Connect the hand-held tester to the DLC3.
Start the engine.

Select the item "WHEEL SPEED FL (FR)" in the DATA LIST and read the value displayed on the hand-held tester.

DATA LIST

Item	Measurement Item / Range (Display)	Normal Condition
WHEEL SPD FR	Wheel speed sensor (FR) reading / min.: 0 km/h (0 MPH, max.: 326 km/h (202 MPH)	Actual wheel speed
WHEEL SPD FL	Wheel speed sensor (FL) reading / min.: 0 km/h (0 MPH, max.: 326 km/h (202 MPH)	Actual wheel speed

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.
Standard:

There is almost no difference in the displayed speed value.

HINT:

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

OK: Go to step 5

NG: Go to Next Step.

INSPECT FRONT SPEED SENSOR

Make sure that there is no looseness at the connector's locking part and connecting part of the connector A6 or A7.
Disconnect the speed sensor connector.

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

Standard:

LH:

TESTER CONNECTION SPECIFIED CONDITION LH (1 OF 4)

Tester Connection	Specified Condition
A6-2 (FL+) - A6-1 (FL-)	0.92 to 1.22 kΩ

RH:

TESTER CONNECTION SPECIFIED CONDITION RH (1 OF 4)

Tester Connection	Specified Condition
A7-2(FR+) -A7-1 (FR-)	0.92 to 1.22 kΩ

Fig 1: Measuring Front Speed Sensor Resistance

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

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

Standard:

LH:

TESTER CONNECTION SPECIFIED CONDITION LH (2 OF 4)

Tester Connection	Specified Condition
A6-2 (FL+) - Body ground	10 kΩ or higher
A6-1 (FL-) - Body ground	10kΩ or higher

RH:

TESTER CONNECTION SPECIFIED CONDITION RH (2 OF 4)

Tester Connection	Specified Condition
A7-2 (FR+) - Body ground	10 kΩ or higher
A7-1 (FR-) - Body ground	10 kΩ or higher

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

NG: REPLACE FRONT SPEED SENSOR

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 connectors.

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

Standard:

LH:

TESTER CONNECTION SPECIFIED CONDITION LH (3 OF 4)

Tester Connection	Specified Condition
S1-5(FL+)-A6-2(FL+)	1 $ or less
S1-6(FL-)-A6-1 (FL-)	1 $ or less

RH:

TESTER CONNECTION SPECIFIED CONDITION RH (3 OF 4)

Tester Connection	Specified Condition
S1-10(FR+)-A7-2(FR+)	1 $ or less
S1-9(FR-)-A7-1 (FR-)	1 $ or less

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

Fig 2: Checking Harness And Connector (Front Speed Sensor - Skid Control ECU)

Standard:

LH:

TESTER CONNECTION SPECIFIED CONDITION LH (4 OF 4)

Tester Connection	Specified Condition
A6-2 (FL+) - Body ground	10 kΩ or higher
A6-1 (FR-) - Body ground	10 kΩ or higher

RH:

TESTER CONNECTION SPECIFIED CONDITION RH (4 OF 4)

Tester Connection	Specified Condition
A7-2 (FR+) - Body ground	10 kΩ or higher
A7-1 (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 terminals FR+ - FR- and FL+ - FL- of the skid control ECU.
2. Drive the vehicle at about 19 mph (30 km/h), and check the signal waveform.
  Standard:
  - As 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 3: Normal Signal Waveform
    Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. OK: REPLACE BRAKE ACTUATOR ASSY (See REPLACEMENT )
NG: Go to Next Step.
INSPECT FRONT SPEED SENSOR INSTALLATION
1. Check the speed sensor installation.
  Standard:
  
  There is no clearance between the sensor and front steering knuckle.
  
  The installation bolt is tightened properly.
  
  Torque: 8.0 N.m (82 kgf.cm, 71 in.-lbf)
  
  Fig 4: Inspecting Front Speed Sensor Installation
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
NOTE: Check the speed sensor signal after replacement (See PRE-CHECK ).
1. NG: REPLACE FRONT SPEED SENSOR
OK: Go to Next Step.
INSPECT SPEED SENSOR TIP
1. Remove the front speed sensor (See REPLACEMENT ).
2. Check the sensor tip.
  Standard:
  
  No scratches or foreign matter on the sensor tip.
NOTE: Check the speed sensor signal after cleaning (See PRE-CHECK ).
1. NG: CLEAN OR REPLACE SPEED SENSOR
OK: Go to Next Step.
INSPECT SPEED SENSOR ROTOR
1. Remove the front drive shaft (See FRONT DRIVE SHAFT (FROM JULY, 2003) ).
2. Check the sensor rotor serrations.
  Standard:
  
  No scratches, missing teeth or foreign matter.
  
  HINT:
  
  If foreign matter is attached, remove it and after reassembling, check the output waveform.
  
  NOTE: Check the speed sensor signal after cleaning (See PRE-CHECK ).
  
  Fig 5: Checking Sensor Rotor Serrations
  Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
1. NG: CLEAN OR REPLACE SPEED SENSOR ROTOR
OK: REPLACE BRAKE ACTUATOR ASSY (See REPLACEMENT )