Electronically Controlled Brake System

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C1235/35: Foreign Object is Attached on Tip of Front Speed Sensor RH

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 C1238/38 - Foreign Object is Attached on Tip of Rear Speed Sensor RH

DTC C1239/39 - Foreign Object is Attached on Tip of Rear Speed Sensor LH

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)

DTC C1277/77 - Abnormal Change in Output Signal of Rear Speed Sensor RH (Test Mode DTC)

DTC C1278/78 - Abnormal Change in Output Signal of Rear Speed Sensor LH (Test Mode DTC)

DESCRIPTION

The speed sensor detects wheel speed and sends the appropriate signals to the ECU. These signals are used to control the ABS system. This speed sensor contains a sensor IC, which consists of 2 MREs (Magnetic Resistance Element). The speed sensor rotor, which consists of 48 sets of N and S poles that are arranged in a circle, is integrated with the inner race of the hub bearing.
To detect the rotation direction, the output waves are used to determine the relationship of the pulses that are generated by 2 MREs. Upon receiving this signal, the sensor IC outputs a forward or backward wave to the ECU.
DTCs C1271/71 and C1272/72 can be deleted when the speed sensor sends a vehicle speed signal or the Test Mode ends. DTCs C1271/71 and C1272/72 are output only in the Test Mode.

HINT:
- DTC C1235/35 is for the right front speed sensor.
- DTC C1236/36 is for the left front speed sensor.
- DTC C1238/38 is for the right rear speed sensor.
- DTC C1239/39 is for the left rear speed sensor.

WIRING DIAGRAM

INSPECTION PROCEDURE
NOTICE:
When replacing the skid control ECU, perform initialization of linear solenoid valve and calibration Programming and Relearning.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU TO SPEED SENSOR)

(a) Disconnect the skid control ECU (A13, A15) connectors and each speed sensor connector.
(b) Measure the resistance according to the value(s) in the table below.
Resistance:
RH
LH

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. INSPECT SKID CONTROL ECU (SENSOR INPUT VOLTAGE)

(a) Reconnect the skid control ECU (A13, A15) connectors.
(b) Disconnect each speed sensor connector.
(c) Turn the engine switch on (IG).
(d) Measure the voltage according to the value(s) in the table below.
Voltage:

NG -- REPLACE SKID CONTROL ECU
OK -- Continue to next step.
3. RECONFIRM DTC
(a) Clear the DTC Electronically Controlled Brake System.
(b) Start the engine.
(c) Drive the vehicle at the speed of 20 km/h (12 mph) or more for 60 seconds or more.
(d) Check if the same DTCs are recorded Electronically Controlled Brake System.
HINT:
Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.

Result:

B -- END
A -- Continue to next step.
4. INSPECT SPEED SENSOR TIP
(a) Remove each speed sensor Removal for front, or Removal for rear).
(b) Check the sensor tip.
OK:
No scratches or foreign matter on the sensor tip.
NOTICE:
Check the speed sensor signal after replacement Test Mode Procedure.

NG -- CLEAN OR REPLACE SPEED SENSOR
OK -- Continue to next step.
5. INSPECT SPEED SENSOR ROTOR
(a) Remove the speed sensor rotor.
(b) Check the sensor rotor.
OK:
No scratches, oil, or foreign matter on the rotors.
NOTICE:
Check the speed sensor signal after cleaning/replacement Test Mode Procedure.

NG -- CLEAN OR REPLACE SPEED SENSOR ROTOR
OK -- Continue to next step.
6. RECONFIRM DTC
(a) Clear the DTCs Electronically Controlled Brake System.
(b) Turn the engine switch on (IG).
(c) Check if the same DTCs are recorded Electronically Controlled Brake System.
Result:

B -- REPLACE SKID CONTROL ECU
A -- END