Inspection Procedure

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

CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

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 FR	FR speed sensor open detection / OPEN or NORMAL	NORMAL: Normal condition	-
SPD SEN FL	FL speed sensor open detection / OPEN or NORMAL	NORMAL: Normal condition	-

OK : There are no momentary interruptions.

HINT:

Perform the above inspection before removing the sensor and connector.

NG : Go to step 5

READ VALUE OF INTELLIGENT TESTER (FRONT SPEED SENSOR)

Check the DATA LIST for proper functioning of the front speed sensor.

Skid control ECU

MEASUREMENT ITEM

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

HINT:

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

NG : Go to step 4

CHECK SPEED SENSOR AND SENSOR ROTOR SERRATIONS
1. Connect the oscilloscope to terminal FR+ and FR-, or FL+ and FL- 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 6

Fig 1: Checking Signal Waveform
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : REPLACE SKID CONTROL ECU

INSPECT FRONT SPEED SENSOR

Disconnect the speed sensor connector.

Measure the resistance of the sensors.

Standard resistance:

for LH

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
2 (FL+) - 1 (FL-)	1.4 to 1.8 kΩ
1 (FL-) - Body ground	10 kΩ or higher
2 (FL+) - Body ground	10 kΩ or higher

Fig 2: Measuring Resistance Of Sensors

Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

for RH

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
2 (FR+) - 1 (FR-)	1.4 to 1.8 kΩ
1 (FR-) - Body ground	10 kΩ or higher
2 (FR+) - Body ground	10 kΩ or higher

NOTE: Check the speed sensor signal after 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 FRONT SPEED SENSOR

CHECK WIRE HARNESS (SKID CONTROL ECU - FRONT SPEED SENSOR)

Disconnect the S7 and S10 ECU connectors.
Disconnect the A3 and A4 sensor connectors.

Measure the resistance of the wire harness side connectors.

Standard resistance:

for LH

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
A3-1 (FL-) - S10-22 (FL-)	Below 1 Ω
A3-2 (FL+) - S10-28 (FL+)	Below 1 Ω
A3-2 (FL+) - Body ground	10 kΩ or higher
A3-1 (FL-) - Body ground	10 kΩ or higher

for RH

TESTER CONNECTION SPECIFIED CONDITION

Tester Connection	Specified Condition
A4-1 (FR-) - S7-22 (FR-)	Below 1 Ω
A4-2 (FR+) - S7-32 (FR+)	Below 1 Ω
A4-2 (FR+) - Body ground	10 kΩ or higher
A4-1 (FR-) - Body ground	10 kΩ or higher

NG : REPAIR OR REPLACE HARNESS AND CONNECTOR

Fig 3: Disconnecting S7 And S10 ECU Connectors

CHECK SPEED SENSOR AND SENSOR ROTOR SERRATIONS
1. Connect the oscilloscope to terminals FR+ and FR-, or FL+ and FL- 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 4: Checking Signal Waveform
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : REPLACE SKID CONTROL ECU
INSPECT FRONT SPEED SENSOR INSTALLATION
1. Check the speed sensor installation.
  OK : The installation bolt is tightened properly and there is no clearance between the sensor and front steering knuckle.
  
  Torque: 8.0 N*m (82 kgf*cm, 71 in.*lbf)
  
  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 FRONT SPEED SENSOR

Fig 5: Identifying Clearance Between Sensor And Front Steering Knuckle
Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

OK : REPLACE SKID CONTROL ECU