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

BRAKE CONTROL: ELECTRONICALLY CONTROLLED BRAKE SYSTEM: C0200/31: Front Speed Sensor RH Circuit

DTC C0200/31 - Front Speed Sensor RH Circuit

DTC C0205/32 - Front Speed Sensor LH Circuit

DTC C1271/71 - Low Output Signal of Front Speed Sensor RH (Test Mode DTC)

DTC C1272/72 - Low Output Signal of Front 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 control system. The front rotors have 48 serrations, respectively.
When the rotors rotate, the magnetic field emitted by the permanent magnet in the speed sensor generates 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.
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 C0200/31 is for the right front speed sensor.
- DTC C0205/32 is for the left front speed sensor.
- The BRAKE warning light comes on when speed sensor malfunctions are detected in two or more wheels.

WIRING DIAGRAM

INSPECTION PROCEDURE
NOTE: When replacing the skid control ECU, perform initialization of liner solenoid valve and calibration Initialization.

PROCEDURE

1. CHECK HARNESS AND CONNECTOR (MOMENTARY INTERRUPTION)
(a) Using Techstream, check for any momentary interruption in the wire harness and connector corresponding to a DTC Check For Intermittent Problems.

ABS / VSC / TRAC:

OK:
There are no momentary interruptions.
HINT: Perform the above inspection before removing the sensor and connector.

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR (BETWEEN FRONT SPEED SENSOR AND SKID CONTROL ECU)
OK -- Continue to next step.
2. READ VALUE OF TECHSTREAM (FRONT SPEED SENSOR)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch ON position.
(c) Select the Data List mode on Techstream.

ABS / VSC / TRAC:

(a) Check the sensor installation.
OK:
There is no clearance between the sensor and rear axle carrier.
The installation bolt is tightened properly.
Torque: 8.0 N*m (82 kgf*cm, 71 in.*lbf)
NOTE: Check the speed sensor signal after the replacement Test Mode Procedure.

NG -- CHECK AND REPLACE FRONT SPEED SENSOR
OK -- Continue to next step.
4. INSPECT FRONT SPEED SENSOR

(a) Make sure that there is no looseness at the connector's locking part and connecting part of the connector.
(b) Disconnect the speed sensor connector.
(c) Measure the resistance according to the value(s) in the table below.
Resistance:
LH

(d) Measure the resistance according to the value(s) in the table below.
Resistance:
LH

NOTE: Check the speed sensor signal after replacement Test Mode Procedure.

NG -- REPLACE FRONT SPEED SENSOR
OK -- Continue to next step.
5. CHECK HARNESS AND CONNECTOR (BETWEEN FRONT SPEED SENSOR AND SKID CONTROL ECU)

(a) Disconnect the skid control ECU connectors and the front speed sensor connectors.
(b) Measure the resistance according to the value(s) in the table below.
Resistance:
LH

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- Continue to next step.
6. INSPECT SPEED SENSOR AND SENSOR ROTOR SERRATIONS
(a) Connect the skid control ECU connectors.

(b) Connect the oscilloscope to terminals S38-32 (FR+) and S38-22 (FR-) or S41-28 (FL+) and S41-22 (FL-) of the skid control ECU.
(c) Drive the vehicle at approximately 19 mph (30 km/h), and check the signal waveform.
OK:
A waveform as shown in the figure should be output.
HINT:
- As the vehicle speed (wheel revolution speed) increases, a cycle of the waveform narrows and the fluctuation in the output voltage becomes greater.
- When noise is identified in the waveform on the oscilloscope, error signals are generated due to the speed sensor rotor's scratches, looseness or foreign matter attached to it.

NG -- CLEAN OR REPLACE FRONT SPEED SENSOR AND SENSOR ROTOR
OK -- Continue to next step.
7. READ VALUE OF TECHSTREAM (FRONT SPEED SENSOR)
(a) Connect Techstream to the DLC3.
(b) Turn the ignition switch on.
(c) Select the Data List mode on Techstream.

ABS / VSC / TRAC:

(d) Check that there is no difference between the speed value output from the speed sensor displayed on Techstream and the speed value displayed on the speedometer when driving the vehicle.
OK:
There is almost no difference from the displayed speed value.
HINT: There is tolerance of ± 10 % in the speedometer indication.

NG -- REPLACE SKID CONTROL ECU
OK -- END
8. PERFORM TEST MODE (SIGNAL CHECK)
(a) Perform sensor signal check in TEST MODE PROCEDURE Test Mode Procedure.
OK:
All test mode DTCs are erased.
NG -- INSPECT FRONT SPEED SENSOR INSTALLATION
OK -- Continue to next step.
9. INSPECT SPEED SENSOR AND SENSOR ROTOR SERRATIONS

(a) Connect the oscilloscope to terminals S38-32 (FR+) and S38-22 (FR-) or S41-28 (FL+) and S41-22 (FL-) of the skid control ECU.
(b) Drive the vehicle at approximately 19 mph (30 km/h), and check the signal waveform.
OK:
A waveform as shown in the figure should be output.
HINT:
- As the vehicle speed (wheel revolution speed) increases, a cycle of the waveform narrows and the fluctuation in the output voltage becomes greater.
- When noise is identified in the waveform on the oscilloscope, error signals are generated due to the speed sensor rotor's scratches, looseness or foreign matter attached to it.

NG -- CLEAN OR REPLACE FRONT SPEED SENSOR AND SENSOR ROTOR
OK -- END
10. REPAIR OR REPLACE HARNESS OR CONNECTOR (BETWEEN FRONT SPEED SENSOR AND SKID CONTROL ECU)
NEXT -- Continue to next step.
11. RECONFIRM DTC
(a) Clear the DTC Reading and Clearing Diagnostic Trouble Codes.
(b) Turn the ignition switch on.
(c) Drive the vehicle at the speed of 20 mph (32 km/h) or more, for 60 seconds or more, and drive in reverse at a speed of 2 mph (3 km/h) or more, for approximately 5 seconds.
(d) Check that the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.
HINT: Reinstall the sensors, connectors, etc. and restore the previous vehicle conditions before rechecking for DTCs.

Result:

B -- READ VALUE OF TECHSTREAM (FRONT SPEED SENSOR)
A -- END