Inspection Procedure

1. Using the hand-held tester, check for any momentary interruption in the wire harness and connector corresponding to a DTC (see CHECK FOR INTERMITTENT PROBLEMS  ).

OK: Go To Next Step 

There are no momentary interruptions. 

HINT:

Perform the above inspection before removing the sensor and connector.

NG: Go to step   5 

OK: Go To Next Step 

1. Connect the hand-held tester to the DLC3.
2. Turn the power switch ON (READY).
3. Select the DATA LIST mode on the hand-held tester.
   FRONT SPEED SENSOR NORMAL CONDITION
   
   

   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

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.

OK: Go To Next Step 

There is almost no difference from the displayed speed value. 

HINT:

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

NG: Go to step   4 

OK: Go To Next Step 

INSPECTION USING OSCILLOSCOPE 

1. Connect the oscilloscope to terminal FR+ - FR- or FL+ - FL- of the skid control ECU.
2. Drive the vehicle at approximately 19 mph (30 km h), and check the signal waveform.
   Fig 1: Normal Signal Waveform

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK: Go To Next Step 

   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.

   NG: Go to step   6 

   OK: REPLACE SKID CONTROL ECU ASSY (SEE  SKID CONTROL ECU ASSY  ) 

   NOTE: When replacing the skid control ECU assy, perform initialization of linear solenoid valve and calibration (see INITIALIZATION  ).

1. Make sure that there is no looseness at the connector's locking part and connecting part of the connector A3 or A4.
2. Disconnect the speed sensor connector.
3. Measure the resistance according to the value(s) in the table below.
   Fig 2: Measuring Resistance

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard: 

   LH: 

   LH FRONT SPEED SENSOR SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   A3-2 (FL+) - A3-1 (FL-)	1.4 to 1.8 kΩ

   RH: 

   RH FRONT SPEED SENSOR SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   A4-2 (FR+) - A4-1 (FR-)	1.4 to 1.8 kΩ

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

   Standard: 

   LH: 

   LH RESISTANCE REFERENCE
   
   

   Tester Connection	Specified Condition
   A3-1 (FL-) - Body ground	10 kΩ or higher
   A3-2 (FL+) - Body ground	10 kΩ or higher

   RH: 

   RH RESISTANCE REFERENCE
   
   

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

   NOTE: Check the speed sensor signal after replacement (see TEST MODE PROCEDURE  ).

   NG: REPLACE FRONT SPEED SENSOR (SEE  FRONT SPEED SENSOR  ) 

   OK: Go To Next Step 

1. Disconnect the skid control ECU connector and the front speed sensor connector.
2. Measure the resistance according to the value(s) in the table below.
   Fig 3: Disconnecting Skid Control ECU Connector & Front Speed Sensor Connector & Measuring Resistance

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   Standard: 

   LH: 

   LH RESISTANCE SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   A3-1 (FL-) - S10-22 (FL-)	Below1 Ω
   A3-2 (FL+) - S10-28 (FL+)	Below1 Ω

   RH: 

   RH RESISTANCE SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   A4-1 (FR-) - S7-22 (FR-)	Below1 Ω
   A4-2 (FR+) - S7-32 (FR+)	Below1 Ω

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

   Standard: 

   LH: 

   LH TESTER CONNECTION AND RESISTANCE SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   A3-2 (FL+) - Body ground	10 kΩ or higher
   A3-1 (FL-) - Body ground	10 kΩ or higher

   RH: 

   RH TESTER CONNECTION AND RESISTANCE SPECIFIED CONDITION
   
   

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

   NG: REPAIR OR REPLACE HARNESS OR CONNECTOR 

   OK: Go To Next Step 

INSPECTION USING OSCILLOSCOPE 

1. Connect the oscilloscope to terminals FR+ - FR- or FL+ - FL- of the skid control ECU.
2. Drive the vehicle at approximately 19mph (30 km/h), and check the signal waveform.

Fig 4: Normal Signal Waveform

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK: Go To Next Step 

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.

NG: Go to step 7 

OK: Go To Next Step 

REPAIR OR REPLACE SKID CONTROL ECU ASSY (SEE  SKID CONTROL ECU ASSY  )