Dtc C1273 Low Output Signal Of Rear Speed Sensor Rh (Test Mode Dtc)

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

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

CHECK REAR SPEED SENSOR INSTALLATION

READ VALUE USING TECHSTREAM (REAR SPEED SENSOR)

DTC C1273 Low Output Signal of Rear Speed Sensor RH (Test Mode DTC)

DTC C1274 Low Output Signal of Rear Speed Sensor LH (Test Mode DTC)

DTC C1403 Rear Speed Sensor RH Malfunction

DTC C1404 Rear 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 C1273 Low Output Signal Of Rear 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
C1403
C1404
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 less than 10 km/h (6 mph), 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)
  1. Rear speed sensor RH/LH
  2. Speed sensor rotor

Test Mode Diagnosis Code
DTC No.
DTC Detection Condition
Trouble Area
C1273
C1274
Detected only during Test Mode.
  1. Rear speed sensor RH/LH
  2. Speed sensor rotor
HINT:
  1. DTC C1403 and C1273 are for the rear speed sensor RH.
  2. DTC C1404 and C1274 are for the rear speed sensor LH.

WIRING DIAGRAM


Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan). Dtc C1273 Low Output Signal Of Rear Speed Sensor Rh (Test Mode Dtc)


INSPECTION PROCEDURE

NOTICE:
Disassembly of the speed sensor from the rear axle hub and bearing assembly is prohibited.
1.CHECK REAR SPEED SENSOR INSTALLATION

  1. Turn the ignition switch off.



    Yaris. Ncp93, 131.Brake Control Dynamic Control Systems.Anti-Lock Brake System (For Sedan). Dtc C1273 Low Output Signal Of Rear Speed Sensor Rh (Test Mode Dtc)

  1. Check the speed sensor installation.

    OK:
    There is no clearance between the sensor and the rear axle hub.
    HINT:
    Because the rear axle hub and bearing assembly cannot be disassembled, if the rear speed sensor needs replacement, replace the rear axle hub and bearing assembly.
Text in Illustration
*a
Normal
*b
Abnormal
*c
Clearance


NG
REPLACE REAR AXLE HUB AND BEARING ASSEMBLY (YARIS_NCP93 RM000001IWU01CX.html)
OK


2.READ VALUE USING TECHSTREAM (REAR SPEED SENSOR)

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

  1. Enter the following menu: 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
    RR Wheel Speed
    		RR 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
    RL Wheel Speed
    		RL 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).
    NOTICE:
    Check the speed sensor signal after replacement (YARIS_NCP93 RM000000XHT09FX.html).
    HINT:
    1. The rear speed sensor rotor is incorporated into the rear axle hub and bearing assembly.
      If the rear speed sensor rotor needs to be replaced, replace it together with the rear axle hub and bearing assembly with rear speed sensor.
    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).


NG
REPLACE REAR AXLE HUB AND BEARING ASSEMBLY (YARIS_NCP93 RM000001IWU01CX.html)
OK

END