C1274

BRAKE CONTROL: VEHICLE STABILITY CONTROL SYSTEM: C0210/33, C0215/34, C1273/73, C1274/74: Rear 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 field 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 C1273/73 and C1274/74 can be deleted when the speed sensor sends a wheel speed signal or the Test Mode ends. DTCs C1273/73 and C1274/74 are output only in the Test Mode.

HINT
- DTCs C0210/33 and C1273/73 are for the rear speed sensor RH.
- DTCs C0215/34 and C1274/74 are for the rear speed sensor LH.

WIRING DIAGRAM

INSPECTION PROCEDURE

NOTICE:
When replacing the brake actuator assembly, perform zero point calibration Programming and Relearning.

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.

B -- REPAIR OR REPLACE HARNESS OR CONNECTOR (SKID CONTROL ECU - REAR SPEED SENSOR)

C -- CHECK REAR SPEED SENSOR INSTALLATION
A -- Continue to next step.

2. READ VALUE USING TECHSTREAM (REAR 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 REAR 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 REAR 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 REAR SPEED SENSOR

A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)

5. CHECK REAR SPEED SENSOR INSTALLATION

(a) Turn the engine switch off.

(b) Check the speed sensor installation.

OK:

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

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

6. INSPECT REAR SPEED SENSOR

(a) Turn the engine switch off.

(b) Disconnect the rear speed sensor connector.

(c) 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 REAR SPEED SENSOR
OK -- Continue to next step.

7. CHECK HARNESS AND CONNECTOR (SKID CONTROL SENSOR WIRE)

(a) Disconnect the skid control sensor wire.

(b) 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 SKID CONTROL SENSOR WIRE
OK -- Continue to next step.

8. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - REAR 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 skid control sensor wire.

(b) Reconnect the rear speed sensor connector.

(c) Connect an oscilloscope to the rear speed sensor terminal of the skid control ECU.

(d) Check that 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 - REAR 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 rear 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: