Inspection Procedure

1. Check the size and condition of all 4 tires.

   HINT:

   This DTC is output when tire deformation or a difference in tire size is detected.

   OK: 

   The diameter of all 4 tires and air pressure are the same. 

NG: REPLACE TIRES SO THAT ALL 4 TIRES ARE SAME IN SIZE 

OK: Go to next step 

1. INSPECTION USING OSCILLOSCOPE
   1. Disconnect the skid control ECU connector.
   2. Connect the oscilloscope to each speed sensor terminal of the skid control ECU connector.
      CONNECTOR TERMINAL REFERENCE CHART
      
      

      Connector	Circuit
      A40-5 (FL+) - A40-6 (FL-)	Front left speed sensor
      A40-10 (FR+) - A40-9 (FR-)	Front right speed sensor
      A40-7 (RL+) - A40-17 (RL-)	Rear left speed sensor
      A40-19 (RR+) - A40-8 (RR-)	Rear right speed sensor

      Fig 1: Identifying Skid Control ECU Connector Terminals

      Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   3. Check that a waveform is output when the tires are rotated (by the sensor circuit).

      OK: 

      A waveform as shown in the figure should be output. 

      HINT:

      • Each sensor circuit outputs the same waveform without noise.
      • As vehicle speed (wheel rotation speed) increases, the width 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 rotor scratches, looseness or foreign matter attached to the speed sensor.
        Fig 2: Signal Waveform Graph

        Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
   4. Make sure that the waveform does not change while jiggling a connector or a wire harness.

      OK: 

      The waveform does not change. 

      HINT:

      If the waveform changes while jiggling a connector or a wire harness, there may be a malfunction in the connector on the wire harness.

      Result 

      RESULT CHART
      
      

      Result	Proceed to
      OK	A
      NG (waveform changes while jiggling a connector or a wire harness)	B
      NG (waveform does not change while jiggling a connector or a wire harness)	C

B : REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL ECU TO SPEED SENSOR) 

C : CHECK OR REPLACE SPEED SENSOR AND SENSOR ROTOR 

A: Go to next step 

1. Clear the DTC.
2. Start the engine.
3. Drive the vehicle at the speed of 20 mph (32 km/h) or more for 60 seconds or more.
4. Check that the same DTC is recorded.

   Result 

   RESULT CHART
   
   

   Result	Proceed to
   DTC is not output	A
   DTC is output	B

B : REPLACE BRAKE ACTUATOR ASSEMBLY 

A : END