C1271

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 wheel speed and sends the appropriate signals to the skid control ECU. 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.

HINT
When testing voltage, perform the test while the connector between the sensor and ECU is connected. Do not disconnect the connector between the sensor and ECU.









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

WIRING DIAGRAM





INSPECTION PROCEDURE

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

PROCEDURE

1. CHECK FRONT SPEED SENSOR INSTALLATION

(a) Turn the ignition switch off.

(b) 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





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

2. INSPECT FRONT SPEED SENSOR TIP

(a) Remove the front speed sensor Removal.

(b) Check the speed sensor tip.

OK:

No scratches, oil, or foreign matter on the sensor tip.

NOTICE:
If no damage to the speed sensor tip is found during this inspection, do not replace the speed sensor.

HINT
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.

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

3. INSPECT FRONT SPEED SENSOR ROTOR

(a) Remove the front speed sensor rotor Removal.

(b) Check the speed sensor rotor.

OK:

No scratches, oil, or foreign matter on the rotors.

HINT
The front speed sensor rotor is incorporated into the front axle hub bearing.

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

4. READ VALUE USING TECHSTREAM (FRONT SPEED SENSOR)

(a) Install the front speed sensor and the front speed sensor rotor.

(b) Connect the Techstream to the DLC3.

(c) Turn the ignition switch to ON.

(d) Turn the Techstream on.

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

(f) According to the display on the Techstream, read the Data List.

ABS/VSC/TRAC





(g) 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 On-Vehicle Inspection.

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 Problem Symptoms Table.

NG -- REPLACE FRONT SPEED SENSOR

OK -- CHECK FOR INTERMITTENT PROBLEMS How To Proceed With Troubleshooting

5. REPLACE FRONT SPEED SENSOR

(a) Turn the ignition switch off.

(b) Replace the front speed sensor Removal.

NEXT -- Continue to next step.

6. RECONFIRM DTC

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

(b) Start the engine.

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

(d) Check if the same DTC is recorded Reading and Clearing Diagnostic Trouble Codes.

Result





HINT
* The front speed sensor rotor is incorporated into the front axle hub bearing.
* If troubleshooting has been carried out according to the Problem Symptoms Table, refer back to the table and proceed to the next step Problem Symptoms Table.

B -- REPLACE FRONT SPEED SENSOR ROTOR Removal

A -- END