DTC C1401: Front Speed Sensor RH Malfunction; DTC C1402: Front Speed Sensor LH Malfunction: Procedure

1. Check the speed sensor installation (for 2WD).
   Fig 1: Checking Front Speed Sensor Installation

   Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

   OK

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

2. Check the speed sensor installation (for 4WD).

   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)

   Result

   Result	Proceed to
   OK (for 4WD)	A
   OK (for 2WD)	B
   NG (for 2WD)	C
   NG (for 4WD)	D

D → See step   8 

C → See step   7 

B → See step   4 

A: Go to next step 

1. Remove the front speed sensor. Refer to REMOVAL .
2. Check the speed sensor tip.

   OK

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

   NOTE:

   Check the speed sensor signal after cleaning or replacement. Refer to TEST MODE PROCEDURE .

NG → CLEAN OR REPLACE FRONT SPEED SENSOR 

OK: Go to next step 

1. Remove the front speed sensor rotor. Refer to REMOVAL .
2. Check the speed sensor rotor.

   OK

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

   NOTE:

   Check the speed sensor signal after cleaning or replacement. Refer to TEST MODE PROCEDURE .

   HINT: 

   The front speed sensor rotor is incorporated into the front axle hub sub-assembly.

   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: Go to next step 

1. Install the front speed sensor and the front speed sensor rotor.
2. Connect the Techstream to the DLC3.
3. Start the engine.
4. Select the Data List on the Techstream. Refer to DATA LIST / ACTIVE TEST .
   DATA LIST
   
   

   Tester Display	Measurement Item/Range	Normal Condition	Diagnostic Note
   FR Wheel Speed	FR wheel speed sensor reading / min.: 0 km/h (0 mph), max.: 326.4 km/h (202 mph)	When vehicle is stopped: 0 km/h (0 mph) When vehicle is being driven at a constant speed: No major fluctuation	Similar speed as indicated on speedometer
   FL Wheel Speed	FL wheel speed sensor reading /min.: 0 km/h (0 mph), max.: 326.4 km/h (202 mph)	When vehicle is stopped: 0 km/h (0 mph) When vehicle is being driven at a constant speed: No major fluctuation	Similar speed as indicated on speedometer

5. Check the speed value output from the speed sensor displayed on the Techstream.

   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. Refer to ON-VEHICLE INSPECTION .

   OK

   The speed value output from the speed sensor displayed on the Techstream is the similar speed as indicated on the speedometer.

   Result

   Result	Proceed to
   NG (for 4WD)	A
   NG (for 2WD)	B
   OK	C

   NOTE:

   Check the speed sensor signal after replacement. Refer to TEST MODE PROCEDURE .

   HINT: 

   • The front speed sensor rotor is incorporated into the front axle hub sub-assembly.

     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 step. Refer to PROBLEM SYMPTOMS TABLE .

C → See step   9 

B → REPLACE FRONT SPEED SENSOR AND FRONT SENSOR ROTOR 

A: Go to next step 

1. Turn the engine switch off.
2. Replace the front speed sensor. Refer to REMOVAL .
   NOTE:

   Check the speed sensor signal after replacement. Refer to TEST MODE PROCEDURE .

NEXT: Go to next step 

1. Clear the DTCs. Refer to DTC CHECK / CLEAR .
2. Start the engine.
3. Drive the vehicle at a speed of 40 km/h (25 mph) or more for at least 60 seconds.
4. Check if the same DTC is recorded. Refer to DTC CHECK / CLEAR .

   Result

   Result	Proceed to
   DTCs (C1401 and C1402) are not output	A
   DTCs (C1401 and/or C1402) are output	B

   NOTE:

   Check the speed sensor signal after replacement. Refer to TEST MODE PROCEDURE .

   HINT: 

   • The front speed sensor rotor is incorporated into the front axle hub sub-assembly.

     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 step. Refer to PROBLEM SYMPTOMS TABLE .

B → REPLACE FRONT SPEED SENSOR ROTOR 

A → END