C1276

BRAKE CONTROL: ANTI-LOCK BRAKE SYSTEM: C0200/31: Right Front Wheel Speed Sensor Signal Malfunction

DTC C0200/31 - Right Front Wheel Speed Sensor Signal Malfunction

DTC C0205/32 - Left Front Wheel Speed Sensor Signal Malfunction

DTC C1235/35 - Foreign Object is Attached on Tip of Front Speed Sensor RH

DTC C1236/36 - Foreign Object is Attached on Tip of Front Speed Sensor LH

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)

DTC C1275/75 - Abnormal Change in Output Signal of Front Speed Sensor RH (Test Mode DTC)

DTC C1276/76 - Abnormal Change in Output Signal of Front Speed Sensor LH (Test Mode DTC)

DESCRIPTION

The speed sensor detects wheel speed and transmits the appropriate signals to the ECU. These signals are used for control of the ABS control system. Each of the front and rear rotors has 48 serrations.
When the rotors rotate, the magnetic field generated by the permanent magnet in the speed sensor induces 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, C1272/72, C1275/75 and C1276/76 can be deleted when the speed sensor sends a vehicle speed signal or the test mode ends. DTCs C1271/71, C1272/72, C1275/75 and C1276/76 are out put only in the test mode.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. CHOOSE DIAGNOSIS METHOD
(a) Choose the diagnosis method.

Method:

B -- INSPECT FRONT SPEED SENSOR
A -- Continue to next step.
2. READ VALUE OF INTELLIGENT TESTER (FRONT SPEED SENSOR)
(a) Connect the intelligent tester to the DLC3.
(b) Start the engine.
(c) Select the tester menus: DIAGNOSTIC, OBD/MOBD, ABS/VSC and DATA LIST.
(d) Read the WHEEL SPD FR and WHEEL SPD FL status.

OK:
There is almost no difference from the displayed speed value.
HINT: There is tolerance of +- 10% in the speedometer indication.

NG -- INSPECT FRONT SPEED SENSOR
OK -- Continue to next step.
3. INSPECT SPEED SENSOR AND SENSOR ROTOR SERRATIONS

(a) INSPECTION USING OSCILLOSCOPE:
(1) Connect the oscilloscope between terminals FR+ and FR-, or FL+ and FL- of the skid control ECU connector.
(2) Drive the vehicle at about 30 km/h (19 mph), and check the signal waveform.
OK:
A waveform as shown in the figure should be output.
- 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 attached to it.

OK -- REPLACE BRAKE ACTUATOR ASSEMBLY
NG -- Continue to next step.
4. INSPECT FRONT SPEED SENSOR

(a) Make sure that there is no looseness at the locking part and connecting part of connectors.
(b) Disconnect the S2 and S3 speed sensor connectors.
(c) Measure the resistance of the speed sensors.
Standard resistance:

LH

HINT: Check the speed sensor signal after replacement.

NG -- REPLACE FRONT SPEED SENSOR
OK -- Continue to next step.
5. CHECK WIRE HARNESS (SKID CONTROL ECU - FRONT SPEED SENSOR)

(a) Disconnect the S1 skid control ECU connector.
(b) Disconnect the S2 and S3 front speed sensor connectors.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:
LH

NG -- REPAIR OR REPLACE HARNESS AND CONNECTOR
OK -- Continue to next step.
6. INSPECT SPEED SENSOR AND SENSOR ROTOR SERRATIONS

(a) INSPECTION USING OSCILLOSCOPE:
(1) Connect the oscilloscope to terminal FR+ and FR-, or FL+ and FL- of the skid control ECU connector.
(2) Drive the vehicle at about 30 km/h (19 mph), and check the signal waveform.
OK:
A waveform as shown in the figure should be output.
- 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 attached to it.

OK -- REPLACE BRAKE ACTUATOR ASSEMBLY
NG -- Continue to next step.
7. INSPECT FRONT SPEED SENSOR INSTALLATION

(a) 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: 9.0 Nm (92 kgf-cm, 80 in-lbf)
HINT: Check the speed sensor signal after replacement Test Mode Procedure.

NG -- REPLACE FRONT SPEED SENSOR
OK -- Continue to next step.
8. INSPECT SPEED SENSOR TIP
(a) Remove the front speed sensor.
(b) Check the sensor tip.
OK:
No scratches or foreign matter on the sensor tip.
HINT: Check the speed sensor signal after cleaning / replacement Test Mode Procedure.

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

(a) Remove the front drive outboard joint shaft assembly.
(b) Check the sensor rotor serrations.
OK:
No scratches, missing teeth or foreign matter on the rotors.
HINT:
- If there is foreign matter in the rotor, remove it and check the output waveform after reassembly.
- Check the speed sensor signal after cleaning / replacement Test Mode Procedure.

NG -- CLEAN OR REPLACE SENSOR ROTOR
OK -- REPLACE BRAKE ACTUATOR ASSEMBLY