C1238
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 brake control 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 signals from the speed sensor are used to determine the relationship of the pulses that are generated by the 2 MREs. Upon receiving the speed sensor signal, the sensor IC outputs a forward or backward signal to the ECU.
DTCs C1275/75 to C1278/78 are cleared when the speed sensor sends a vehicle speed signal or test mode ends. DTCs C1275/75 to C1278/78 are output only in test mode.
HINT:
- DTC C1235/35 is for the front speed sensor RH.
- DTC C1236/36 is for the front speed sensor LH.
- DTC C1238/38 is for the rear speed sensor RH.
- DTC C1239/39 is for the rear speed sensor LH.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTE:
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 - SPEED SENSOR)
(a) Disconnect the A19 and A21 ECU connectors.
(b) Disconnect the A55 and A5 sensor connectors.
(c) Disconnect the R56 and S65 sensor connectors.
(d) Measure the resistance according to the value(s) in the table below.
Standard resistance:
for RH
for LH
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
2. CHECK SKID CONTROL ECU (SENSOR INPUT VOLTAGE)
(a) Reconnect the A19 and A21 ECU connectors.
(b) Disconnect the A55 sensor connector.
(c) Disconnect the A5 sensor connector.
(d) Disconnect the R56 sensor connector.
(e) Disconnect the S65 sensor connector.
(f) Turn the engine switch on (IG).
(g) Measure the voltage according to the value(s) in the table below.
Standard voltage:
NG -- REPLACE SKID CONTROL ECU
OK -- Continue to next step.
3. RECONFIRM DTC
(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(b) Start the engine.
(c) Drive the vehicle at a speed of 20 km/h (12 mph) or more for 60 seconds or more.
(d) Check if the same DTCs are recorded Reading and Clearing Diagnostic Trouble Codes.
HINT: Reinstall the sensors, connectors, etc. and restore the vehicle to its prior condition before rechecking for DTCs.
Result
C -- CHECK FOR INTERMITTENT PROBLEMS
B -- REPLACE FRONT AXLE HUB SUB-ASSEMBLY
A -- Continue to next step.
4. INSPECT SPEED SENSOR TIP
(a) Remove the front speed sensor Removal and/or rear speed sensor Removal.
(b) Check the sensor tip.
OK:
No scratches or foreign matter on the sensor tip.
NOTE:
Check the speed sensor signal after cleaning or replacement Test Mode Procedure.
NG -- CLEAN OR REPLACE SPEED SENSOR
OK -- Continue to next step.
5. INSPECT SPEED SENSOR ROTOR
(a) Remove the front axle hub sub-assembly Removal.
(b) Remove the rear axle hub and bearing assembly Removal.
(c) Check each sensor rotor.
OK:
No scratches, oil, or foreign matter on the rotors.
HINT:
- The front speed sensor rotor is built into the front axle hub sub-assembly.
- The rear speed sensor rotor is built into the rear axle hub and bearing assembly.
- If the front and/or rear speed sensor rotor needs to be replaced, replace the front axle hub sub-assembly or rear axle hub and bearing assembly.
NOTE:
Check the speed sensor signal after cleaning or replacement Test Mode Procedure.
OK -- RECONFIRM DTC
NG -- CLEAN OR REPLACE SPEED SENSOR ROTOR
6. REPLACE FRONT AXLE HUB SUB-ASSEMBLY
(a) Replace the front axle hub sub-assembly Removal.
HINT: The front speed sensor and front speed sensor rotor are built into the front axle hub sub-assembly.
NEXT -- Continue to next step.
7. RECONFIRM DTC
(a) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.
(b) Turn the engine switch on (IG).
(c) Check if the same DTCs are recorded Reading and Clearing Diagnostic Trouble Codes.
Result
B -- REPLACE SKID CONTROL ECU
A -- CHECK FOR INTERMITTENT PROBLEMS