Dtc C1271 Low Output Signal Of Front Speed Sensor Rh (Test Mode Dtc)

Brake. Yaris. Ncp93, 131
Brake Control Dynamic Control Systems. Yaris. Ncp93, 131

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK FRONT SPEED SENSOR INSTALLATION

INSPECT FRONT SPEED SENSOR TIP

INSPECT FRONT SPEED SENSOR ROTOR

READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR)

REPLACE FRONT SPEED SENSOR

RECONFIRM DTC

DTC C1271 Low Output Signal of Front Speed Sensor RH (Test Mode DTC)

DTC C1272 Low Output Signal of Front Speed Sensor LH (Test Mode DTC)

DTC C1401 Front Speed Sensor RH Malfunction

DTC C1402 Front Speed Sensor LH Malfunction


DESCRIPTION

The speed sensor detects wheel speed and sends the appropriate signals to the skid control ECU (brake actuator assembly). These signals are used for ABS control.
Speed sensor rotors have rows of alternating N and S magnetic poles, and their magnetic fields change when the rotors turn.
Each speed sensor detects that magnetic change and sends a pulse signal to the skid control ECU (brake actuator assembly).
HINT:
When the connectors between the speed sensor and skid control ECU are connected, the following waveform is output.

Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan). Dtc C1271 Low Output Signal Of Front Speed Sensor Rh (Test Mode Dtc)


Text in Illustration
*1
Speed Sensor
*2
Speed Sensor Rotor
*a
Waveform (Reference):
Between Speed Sensor (-) and Body Ground
*b
Low speed
*c
High speed
-
-

DTC No.
DTC Detection Condition
Trouble Area
C1401
C1402
Any of the following is detected:
  1. At a vehicle speed of 10 km/h (6 mph) or more, output voltage from one of the speed sensors is less than that from the other sensors for 15 seconds or more.
  2. At a vehicle speed less than 10 km/h (6 mph), output from one of the speed sensors is 0 km/h (0 mph) for 1 second or more.
  3. At a vehicle speed of 10 km/h (6 mph) or more, outputs from both speed sensors are 0 km/h (0 mph) for 15 seconds or more. (except both rear speed sensors are 0 km/h (0 mph))
  1. Front speed sensor RH/LH
  2. Speed sensor rotor
  3. Sensor installation

Test Mode Diagnosis Code
DTC No.
DTC Detection Condition
Trouble Area
C1271
C1272
Detected only during Test Mode.
  1. Front speed sensor RH/LH
  2. Speed sensor rotor
  3. Sensor installation
HINT:
  1. DTC C1401 and C1271 are for the front speed sensor RH.
  2. DTC C1402 and C1272 are for the front speed sensor LH.

WIRING DIAGRAM


Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan). Dtc C1271 Low Output Signal Of Front Speed Sensor Rh (Test Mode Dtc)


INSPECTION PROCEDURE

1.CHECK FRONT SPEED SENSOR INSTALLATION

  1. Turn the ignition switch off.



    Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan). Dtc C1271 Low Output Signal Of Front Speed Sensor Rh (Test Mode Dtc)

  1. 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:
    8.5 N*m (87 kgf*cm, 75 in.*lbf)
Text in Illustration
*a
Normal
*b
Abnormal
*c
Clearance


NG
INSTALL FRONT SPEED SENSOR CORRECTLY (YARIS_NCP93 RM000001BXU01LX.html)
OK


2.INSPECT FRONT SPEED SENSOR TIP

  1. Remove the front speed sensor (YARIS_NCP93 RM000001BXX01FX.html).

  1. Check the speed sensor tip.

    OK:
    No scratches, oil, or foreign matter on the sensor tip.
    NOTICE:
    1. If there is iron powder sticking to the rotor, this will result in a malfunction, so confirm that the rotor is not contaminated with foreign material before replacing the sensor.
    2. Check the speed sensor signal after cleaning or replacement (YARIS_NCP93 RM000000XHT09FX.html).

  1. Reinstall the front speed sensor (YARIS_NCP93 RM000001BXU01LX.html)



NG
CLEAN OR REPLACE FRONT SPEED SENSOR
OK


3.INSPECT FRONT SPEED SENSOR ROTOR

  1. Remove the front axle hub sub-assembly (YARIS_NCP93 RM000001IWN01EX.html).

  1. Check the speed sensor rotor.

    OK:
    No scratches, oil, or foreign matter on the rotors.
    NOTICE:
    Check the speed sensor signal after cleaning or replacement (YARIS_NCP93 RM000000XHT09FX.html).
    HINT:
    If the front axle hub assembly needs to be replaced, replace it together with the front drive outboard joint shaft assembly.

  1. Reinstall the front axle hub assembly (YARIS_NCP93 RM000001IWO01KX.html).



NG
CLEAN OR REPLACE FRONT SPEED SENSOR ROTOR
OK


4.READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR)

  1. Connect the Techstream to the DLC3.

  1. Start the engine.

  1. Turn the Techstream on.

  1. Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

  1. According to the display on the Techstream, read the Data List.

    ABS/VSC/TRAC (Skid Control ECU)
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    FR Wheel Speed
    		FR wheel speed sensor reading / min.: 0 km/h (0 mph), max.: 326 km/h (202 mph)
    		Vehicle stopped: 0 km/h
    		When driving at constant speed: No large fluctuations
    FL Wheel Speed
    		FL wheel speed sensor reading /min.: 0 km/h (0 mph), max.: 326 km/h (202 mph)
    		Vehicle stopped: 0 km/h
    		When driving at constant speed: No large fluctuations

  1. Check that there is no difference between the speed value output from the speed sensor displayed on the Techstream and the speed value displayed on the speedometer when driving the vehicle.

    HINT:
    Factors that affect the indicated vehicle speed include tire size, tire inflation, and tire wear. The speed indicated on the speedometer has an allowable margin of error. This can be tested using a speedometer tester (calibrated chassis dynamometer). For details about testing and the margin of error, see the reference chart (YARIS_NCP93 RM0000014WB073X.html).
    OK:
    The speed value output from the speed sensor displayed on the Techstream is the same as the actual vehicle speed measured using a speedometer tester (calibrated chassis dynamometer).
    HINT:
    If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (YARIS_NCP93 RM000000XHN0C2X.html).
Result
Result
Proceed to
NG
A
OK
B


B
CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) (YARIS_NCP93 RM000000XHS0AZX.html)
A


5.REPLACE FRONT SPEED SENSOR

  1. Turn the ignition switch off.

  1. Replace the front speed sensor (YARIS_NCP93 RM000001BXX01FX.html).

    NOTICE:
    Check the speed sensor signal after replacement (YARIS_NCP93 RM000000XHT09FX.html).

NEXT


6.RECONFIRM DTC

  1. Clear the DTCs (YARIS_NCP93 RM000000XHV0D3X.html).

  1. Start the engine.

  1. Drive the vehicle at a speed of 40 km/h (25 mph) or more for at least 60 seconds.

  1. Check if the same DTC is recorded (YARIS_NCP93 RM000000XHV0D3X.html).

Result
Result
Proceed to
DTCs C1401 and C1402 are not output
A
DTCs C1401 and/or C1402 are output
B
NOTICE:
Check the speed sensor signal after replacement (YARIS_NCP93 RM000000XHT09FX.html).
HINT:
  1. If the front axle hub assembly needs to be replaced, replace it together with the front drive outboard joint shaft assembly.
  2. If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step (YARIS_NCP93 RM000000XHN0C2X.html).


B
REPLACE FRONT SPEED SENSOR ROTOR (YARIS_NCP93 RM000001BXX01FX.html)
A

END