C1401

BRAKE CONTROL / DYNAMIC CONTROL SYSTEMS: VEHICLE STABILITY CONTROL SYSTEM: C1401, C1271, C1272, C1402: Front Speed Sensor RH Malfunction
C1402 - Front Speed Sensor LH Malfunction

DESCRIPTION

The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU. These signals are used for brake 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 field change and sends a pulse signal to the skid control ECU.

HINT
When the connectors between the speed sensor and skid control ECU are connected, the following waveform is output.









HINT
* DTCs C1401 and C1271 are for the front speed sensor RH.
* DTCs C1402 and C1272 are for the front speed sensor LH.

WIRING DIAGRAM





INSPECTION PROCEDURE

PROCEDURE

1. CHECK FRONT SPEED SENSOR INSTALLATION

(a) Turn the ignition switch off.

(b) Check the speed sensor installation Installation.

OK:

There is no clearance between the sensor and the front steering knuckle.

The installation bolt is tightened properly.

NG -- INSTALL FRONT SPEED SENSOR CORRECTLY Installation
OK -- Continue to next step.

2. INSPECT FRONT SPEED SENSOR TIP C1413

NG -- CLEAN OR REPLACE FRONT SPEED SENSOR
OK -- Continue to next step.

3. INSPECT FRONT SPEED SENSOR ROTOR

(a) Remove the front axle hub sub-assembly Removal.

(b) 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 Test Mode Procedure.

HINT
If the front speed sensor rotor needs to be replaced, replace it together with the front axle hub sub-assembly.

NG -- CLEAN OR REPLACE FRONT SPEED SENSOR ROTOR
OK -- Continue to next step.

4. READ VALUE USING TECHSTREAM (FR/FL WHEEL SPEED)

(a) Turn the ignition switch off.

(b) Connect the Techstream to the DLC3.

(c) Start the engine.

(d) Turn the Techstream on.

(e) Enter the following menus: Chassis / ABS/VSC/TRAC / Data List.

ABS/VSC/TRAC





(f) 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 Operation Check.

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 Problem Symptoms Table, refer back to the table and proceed to the next suspected area Problem Symptoms Table.

NG -- REPLACE FRONT SPEED SENSOR

OK -- CHECK FOR INTERMITTENT PROBLEMS (SYMPTOM SIMULATION) How To Proceed With Troubleshooting

5. REPLACE FRONT SPEED SENSOR

(a) Replace the front speed sensor Removal.

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

NEXT -- Continue to next step.

6. RECONFIRM DTC

(a) Clear the DTCs Reading and Clearing Diagnostic Trouble Codes.

(b) Turn the ignition switch off.

(c) Start the engine.

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

(e) Check if the same DTC is output Reading and Clearing Diagnostic Trouble Codes.

Result





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

HINT
* If the front speed sensor rotor needs to be replaced, replace it together with the front axle hub sub-assembly.
* If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next suspected area Problem Symptoms Table.

B -- REPLACE FRONT AXLE HUB SUB-ASSEMBLY Removal

A -- END