Inspection Procedure

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

   Skid control ECU 

   MEASUREMENT ITEM
   
   

   Item	Measurement Item / Range (Display)	Normal Condition	Diagnostic Note
   SPD SEN RR	RR speed sensor open detection / OPEN or NORMAL	NORMAL: Normal condition	-
   SPD SEN RL	RL speed sensor open detection / OPEN or NORMAL	NORMAL: Normal condition	-

   OK : There are no momentary interruption. 

   HINT:

   Perform the above inspection before removing the sensor and connector.

NG : Go to step   5 

OK 

1. Check the DATA LIST for proper functioning of the rear speed sensor.

   Skid control ECU 

   MEASUREMENT ITEM
   
   

   Item	Measurement Item / Range (Display)	Normal Condition	Diagnostic Note
   WHEEL SPD RL	Wheel speed sensor (RL) reading / min.: 0 km/h (0 mph), max.: 326 km/h (202 mph)	Actual wheel speed	Similar speed as indicated on speedometer
   WHEEL SPD RR	Wheel speed sensor (RR) reading / min.: 0 km/h (0 mph), max.: 326 km/h (202 mph)	Actual wheel speed	Similar speed as indicated on speedometer

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

   HINT:

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

NG : Go to step   4 

OK 

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

   OK : A waveform as shown 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 deposited on it.

NG : Go to step   7 

Fig 1: Checking Signal Waveform

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : REPLACE SKID CONTROL ECU 

1. Disconnect the rear speed sensor connector.
2. Measure the resistance of the sensor.

   Standard resistance 

   TESTER CONNECTION SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   1 - 2	1.04 to 1.30 kΩ
   1 - Body ground	10 kΩ or higher
   2 - Body ground	10 kΩ or higher

NG : REPLACE REAR SPEED SENSOR 

Fig 2: Measuring Resistance Of Sensor

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK 

1. Disconnect the S8 and S9 ECU connectors.
2. Disconnect the A25 and A26 sensor connectors.
3. Measure the resistance of the wire harness side connectors.

   Standard resistance: 

   for LH 

   TESTER CONNECTION SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   A25-1 (RL+) - S8-35 (RL+)	Below 1 Ω
   A25-2 (RL-) - S8-27 (RL-)	Below 1 Ω
   A25-1 (RL+) - Body ground	10 kΩ or higher
   A25-2 (RL-) - Body ground	10 kΩ or higher

   for RH 

   TESTER CONNECTION SPECIFIED CONDITION
   
   

   Tester Connection	Specified Condition
   A26-1 (RR+) - S9-31 (RR+)	Below 1 Ω
   A26-2 (RR-) - S9-23 (RR-)	Below 1 Ω
   A26-1 (RR+) - Body ground	10 kΩ or higher
   A26-2 (RR-) - Body ground	10 kΩ or higher

NG : REPAIR OR REPLACE HARNESS AND CONNECTOR 

Fig 3: Disconnecting S8 And S9 ECU Connectors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK 

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

   OK : A waveform as shown should be output. 

   HINT:

   • 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 deposited on it.

NG : Go to step 7 

Fig 4: Checking Signal Waveform

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : REPLACE SKID CONTROL ECU 

1. Check the sensor installation.

   OK : There is no clearance between the sensor and rear axle carrier. 

   NOTE: Check the speed sensor signal after the replacement (see DTC C0200/31 FRONT SPEED SENSOR RH CIRCUIT; DTC C0205/32 FRONT SPEED SENSOR LH CIRCUIT; DTC C1271/71 LOW OUTPUT SIGNAL OF FRONT SPEED SENSOR RH (TEST MODE DTC); DTC C1272/72 LOW OUTPUT SIGNAL OF FRONT SPEED SENSOR LH (TEST MODE DTC)  ).

NG : REPLACE REAR SPEED SENSOR 

Fig 5: Identifying Clearance Between Sensor And Rear Axle Carrier

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : REPLACE SKID CONTROL ECU