C1239
BRAKE CONTROL: VEHICLE STABILITY CONTROL 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 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.
When foreign matter adheres to the speed sensor tip or speed sensor rotor, or the rotor teeth are chipped, these DTCs are output. An abnormal waveform input from the sensor determines these conditions.
These DTCs may be detected when a malfunction occurs in the connector terminals or wire harness of the speed sensor circuit.
DTCs C1275/75 to C1278/78 can be deleted when the speed sensor sends a vehicle speed signal or the Test Mode ends. DTCs from C1275/75 to C1278/78 are output only in the Test Mode.
HINT:
- DTCs C1235/35 and C1275/75 are for the front speed sensor RH.
- DTCs C1236/36 and C1276/76 are for the front speed sensor LH.
- DTCs C1238/38 and C1277/77 are for the rear speed sensor RH.
- DTCs C1239/39 and C1278/78 are for the rear speed sensor LH.
WIRING DIAGRAM
INSPECTION PROCEDURE
NOTE:
When replacing the brake actuator assembly, perform zero point calibration Programming and Relearning.
HINT: When C0200/31, C0205/32, C0210/33, or C0215/34 is output together with C1235/35, C1236/36, C1238/38, or C1239/39, inspect and repair the trouble areas indicated by C0200/31, C0205/32, C0210/33, or C0215/34 first.
PROCEDURE
1. CHECK SPEED SENSOR AND SPEED SENSOR ROTOR SERRATIONS
(a) Disconnect the skid control ECU connector.
(b) Connect the oscilloscope to each 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 waveform.
(d) Check that the waveform does not change while jiggling a connector or a wire harness.
OK:
The waveform does not change.
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.
NG -- INSPECT EACH SPEED SENSOR
OK -- Continue to next step.
2. 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 20 km/h (12 mph) or more for at least 60 seconds.
(f) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.
Result:
B -- REPLACE BRAKE ACTUATOR ASSEMBLY
A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)
3. INSPECT EACH SPEED SENSOR
(a) Turn the engine switch off.
(b) Disconnect each speed sensor connector.
(c) Measure the resistance according to the value(s) in the table below.
Standard resistance:
RH
LH
Result:
C -- REPLACE EACH SPEED SENSOR
B -- CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - EACH SPEED SENSOR)
A -- Continue to next step.
4. 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
NOTE:
Check the speed sensor signal after replacement Test Mode Procedure.
NG -- REPLACE SKID CONTROL SENSOR WIRE
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (SKID CONTROL ECU - EACH SPEED SENSOR)
(a) Measure the resistance according to the value(s) in the table below.
Standard resistance:
RH
LH
NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. RECONFIRM DTC
(a) Reconnect the skid control sensor wire.
(b) Reconnect the skid control ECU connector and the speed sensor connector.
(c) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(d) Start the engine.
(e) Drive the vehicle at the speed of 20 km/h (12 mph) or more for at least 60 seconds.
(f) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.
Result:
C -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)
B -- CHECK EACH SPEED SENSOR ROTOR
A -- Continue to next step.
7. CHECK FRONT SPEED SENSOR TIP
(a) Turn the engine switch off.
(b) Remove the front speed sensor Removal.
(c) Check the speed 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 FRONT SPEED SENSOR
OK -- Continue to next step.
8. CHECK EACH SPEED SENSOR ROTOR
(a) Turn the engine switch off.
(b) Remove each speed sensor rotor Removal for front, or Removal for rear).
(c) Check the speed sensor rotor.
OK:
No scratches, missing teeth, or foreign matter on the rotors.
NOTE:
Check the speed sensor signal after cleaning or replacement Test Mode Procedure.
NG -- CLEAN OR REPLACE EACH SPEED SENSOR ROTOR
OK -- Continue to next step.
9. RECONFIRM DTC
(a) Install the front speed sensor and the speed sensor rotor.
(b) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(c) Start the engine.
(d) Drive the vehicle at the speed of 20 km/h (12 mph) or more for at least 60 seconds.
(e) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.
Result:
B -- REPLACE BRAKE ACTUATOR ASSEMBLY
A -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION)