DTC Code | DTC Name |
---|---|
C1401 | Front Speed Sensor RH Malfunction |
C1271 | Low Output Signal of Front Speed Sensor RH (Test Mode DTC) |
C1272 | Low Output Signal of Front Speed Sensor LH (Test Mode DTC) |
C1402 | Front Speed Sensor LH Malfunction |
DESCRIPTION
The speed sensor detects the wheel speed and sends the appropriate signals to the skid control ECU (master cylinder solenoid). These signals are used for brake control.
When the connectors between the speed sensor and skid control ECU (master cylinder solenoid) are connected, the following waveform is output.
DTC Code | DTC Detection Condition | Trouble Area |
---|---|---|
C1401 C1402 |
One of the following conditions is met:
|
|
C1271 C1272 |
Stored only during test mode. |
|
DTCs C1401 and C1271 are for the front speed sensor RH.
DTCs C1402 and C1272 are for the front speed sensor LH.
CAUTION / NOTICE / HINT
Check the speed sensor signal after cleaning or replacement (Click here).
PROCEDURE
CHECK FRONT SPEED SENSOR INSTALLATION
Turn the ignition switch off.
Check the speed sensor installation (Click here).
OK |
---|
There is no clearance between the sensor and the front steering knuckle. |
The installation bolt is tightened properly. |
*1 | Front Speed Sensor |
*a | No clearance |
*b | OK |
*c | NG |
INSTALL FRONT SPEED SENSOR CORRECTLY
INSPECT FRONT SPEED SENSOR TIP
Remove the front speed sensor (Click here).
Check the speed sensor tip.
OK |
---|
No scratches, oil, or foreign matter on the sensor tip. |
If no damage to the speed sensor tip is found during this inspection, do not replace the speed sensor.
CLEAN OR REPLACE FRONT SPEED SENSOR
INSPECT FRONT SPEED SENSOR ROTOR
Remove the front axle hub sub-assembly (Click here).
Check the speed sensor rotor.
OK |
---|
No scratches, oil, or foreign matter on the rotors. |
The front speed sensor rotor is incorporated into the front axle with ABS rotor bearing assembly.
If the front speed sensor rotor needs to be replaced, replace it together with the front axle with ABS rotor bearing assembly.
CLEAN OR REPLACE FRONT SPEED SENSOR ROTOR
READ VALUE USING GTS (FR/FL WHEEL SPEED)
Turn the ignition switch off.
Connect the GTS to the DLC3.
Start the engine.
Turn the GTS on.
Enter the following menus: Chassis / ABS/VSC/TRC / Data List.
Tester Display | Measurement Item/Range | Normal Condition | Diagnostic Note |
---|---|---|---|
FR Wheel Speed | Front speed sensor RH reading/ Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) | Actual wheel speed | No large fluctuations when driving at a constant speed. |
FL Wheel Speed | Front speed sensor LH reading/ Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) | Actual wheel speed | No large fluctuations when driving at a constant speed. |
Check that there is no difference between the speed value output from the speed sensor displayed on the GTS and the speed value displayed on the speedometer when driving the vehicle.
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, refer to the reference chart (Click here).
OK |
---|
The speed value output from the speed sensor displayed on the GTS is the same as the actual vehicle speed measured using a speedometer tester (calibrated chassis dynamometer). |
CHECK FOR INTERMITTENT PROBLEMS (Click here)
REPLACE FRONT SPEED SENSOR
Replace the front speed sensor (Click here).
RECONFIRM DTC
Clear the DTC (Click here).
Turn the ignition switch off.
Start the engine.
Drive the vehicle at a speed of 40 km/h (25 mph) or more for at least 60 seconds.
Check if the same DTC is output (Click here).
Result | Proceed to |
---|---|
DTC is not output | A |
DTC is output | B |
END
REPLACE FRONT AXLE WITH ABS ROTOR BEARING ASSEMBLY (Click here)