C1272

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C0200/31,C0205/32,C1271/71,C1272/72: Front Speed Sensor RH Circuit

DESCRIPTION

The speed sensors detect wheel speed and transmit the signals to the ECU. These signals are used for control of the ABS control system. Each of the front and rear rotors have 48 serrations. When the rotors rotate, the magnetic filed generated by the permanent magnet in the speed sensor induces an AC voltage.

Since the frequency of this AC voltage changes in direct proportion to the speed of the rotor, the frequency is used by the ECU to detect the speed of each wheel.

DTCs C1271/71 and C1272/72 can be deleted when the speed sensor sends a wheel speed signal or the Test Mode ends. DTCs C1271/71 and C1272/72 are output only in the Test Mode.

HINT
- DTCs C0200/31 and C1271/71 are for the front speed sensor RH.
- DTCs C0205/32 and C1272/72 are for the front speed sensor LH.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
When replacing the brake actuator assembly, perform zero point calibration Calibration.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)

(a) Using Techstream, check for any momentary interruption in the wire harness and connector corresponding to a DTC Check For Intermittent Problems.

ABS / VSC / TRAC:

Result:

HINT
Perform the above inspection before removing the sensor and connector.

C -- CHECK FRONT SPEED SENSOR INSTALLATION

B -- REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL ECU - FRONT SPEED SENSOR)
A -- Continue to next step.

2. READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR)

(a) Turn the engine switch off.

(b) Connect Techstream to the DLC3.

(c) Start the engine.

(d) Select the Data List on Techstream.

ABS / VSC / TRAC:

(e) Check that there is no difference between the speed value output from the speed sensor displayed on Techstream and the speed value displayed on the speedometer when driving the vehicle.

OK:

The speed value output from the speed sensor displayed on Techstream is the same as the actual vehicle speed.

NG -- CHECK FRONT SPEED SENSOR INSTALLATION
OK -- Continue to next step.

3. PERFORM TEST MODE (SIGNAL CHECK)

(a) Perform sensor check in the Test Mode procedure Test Mode Procedure.

OK:

All Test Mode DTCs are cleared.

NG -- CHECK FRONT SPEED SENSOR INSTALLATION
OK -- Continue to next step.

4. RECONFIRM DTC

(a) Turn the engine switch off.

(b) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

(c) Start the engine.

(d) Drive the vehicle at the speed of 32 km/h (20 mph) or more for at least 60 seconds.

(e) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.

Result:

HINT
If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step Problem Symptoms Table.

B -- INSPECT FRONT SPEED SENSOR

A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)

5. CHECK FRONT SPEED SENSOR INSTALLATION

(a) Turn the engine switch off.

(b) Check the speed sensor installation.

OK:

There is no clearance between the sensor and the front steering knuckle.

The installation bolt is tightened properly.

Torque : 8.0 Nm (82 kgf-cm, 71 in-lbf)

NG -- INSTALL FRONT SPEED SENSOR CORRECTLY
OK -- Continue to next step.

6. CHECK FRONT SPEED SENSOR TIP

(a) Remove the front speed sensor Removal.

(b) Check the speed sensor tip.

OK:

No scratches or foreign matter on the sensor tip.

NOTICE:
Check the speed sensor signal after cleaning or replacement Test Mode Procedure.

NG -- CLEAN OR REPLACE FRONT SPEED SENSOR
OK -- Continue to next step.

7. INSPECT FRONT SPEED SENSOR

(a) Turn the engine switch off.

(b) Install the front speed sensor.

(c) Disconnect the front speed sensor connector.

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

Standard resistance:

RH
LH

Text in Illustration

NOTICE:
Check the speed sensor signal after replacement Test Mode Procedure.

NG -- REPLACE FRONT SPEED SENSOR
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - FRONT SPEED SENSOR)

(a) Disconnect the skid control ECU connector.

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

Standard resistance:

RH
LH

Text in Illustration

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.

9. CHECK SPEED SENSOR AND SPEED SENSOR ROTOR SERRATIONS

(a) Reconnect the front speed sensor connector.

(b) Connect the oscilloscope to the front speed sensor terminal of the skid control ECU.

(c) Check that a waveform is output when the tires are rotated (by the sensor circuit).

OK:

The same waveform is output from all the 4 wheels and there is no noise or interference in the waveform.

HINT
- As the vehicle speed (wheel revolution speed) increases, a cycle of the waveform narrows and the output voltage becomes greater.
- When noise is identified in the waveform on the oscilloscope, the erratic signals are generated due to speed sensor rotor's scratches, looseness or foreign matter attached to it.

Text in Illustration

NOTICE:
Check the speed sensor signal after cleaning or replacement Test Mode Procedure.

NG -- CLEAN OR REPLACE SPEED SENSOR OR SPEED SENSOR ROTOR
OK -- Continue to next step.

10. RECONFIRM DTC

(a) Turn the engine switch off.

(b) Reconnect the skid control ECU connector.

(c) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

(d) Start the engine.

(e) Drive the vehicle at the speed of 32 km/h (20 mph) or more for at least 60 seconds.

(f) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.

Result:

HINT
If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step Problem Symptoms Table.

B -- REPLACE BRAKE ACTUATOR ASSEMBLY

A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)

11. REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL ECU - FRONT SPEED SENSOR)

(a) Turn the engine switch off.

(b) Repair or replace the harness or connector.

(c) Check for any momentary interruption between the skid control ECU and front speed sensor Check For Intermittent Problems.

(d) Check that there is no momentary interruption.

NEXT -- Continue to next step.

12. RECONFIRM DTC

(a) Turn the engine switch off.

(b) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.

(c) Start the engine.

(d) Drive the vehicle at the speed of 32 km/h (20 mph) or more for at least 60 seconds.

(e) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.

Result: