| DTC Code | DTC Name |
|---|---|
| C1271 | Low Output Signal of Front Speed Sensor RH (Test Mode DTC) |
| C1272 | Low Output Signal of Front Speed Sensor LH (Test Mode DTC) |
| C1330 | Open in Front Speed Sensor RH |
| C1331 | Open in Front Speed Sensor LH |
| C1464 | Front Speed Sensor RH |
| C1465 | Front Speed Sensor LH |
DESCRIPTION
Each speed sensor detects wheel speed and sends signals to the skid control ECU (brake actuator assembly). These signals are used by the ABS.
The speed sensor rotors have rows of alternating N and S magnetic poles. The speed sensors use the frequency of output pulses to detect the vehicle speed. Because the sensor outputs digital pulses, it can detect the vehicle speed even when the vehicle is nearly stationary.
DTCs C1271 and C1272 are cleared when the speed sensor sends a vehicle speed signal or when Test Mode ends. DTCs C1271 and C1272 are output only in Test Mode.
Tech Tips
When the connectors between the speed sensor and skid control ECU (brake actuator assembly) are connected, the following waveform is output.
| *1 | Front Speed Sensor | *2 | Speed Sensor Rotor |
| *a | Waveform (Reference): Between Speed Sensor (-) and Body Ground |
*b | Low speed |
| *c | High speed | - | - |
| DTC No. | DTC Detection Condition | Trouble Area |
|---|---|---|
| C1271 | Detected only during Test Mode. |
|
| C1272 | Detected only during Test Mode. |
|
| C1330 | An open or short in the speed sensor signal circuit. |
|
| C1331 | An open or short in the speed sensor signal circuit. |
|
| C1464 | Any of the following is detected:
|
|
| C1465 | Any of the following is detected:
|
|
WIRING DIAGRAM
CAUTION / NOTICE / HINT
Note
When replacing the skid control ECU (brake actuator assembly), perform system variant learning and acceleration sensor zero point calibration Click here.
PROCEDURE
READ VALUE USING GTS (FRONT SPEED SENSOR)
Connect the GTS to the DLC3.
Start the engine.
Select the Data List on the GTS Click here.
| Tester Display | Measurement Item/Range | Normal Condition | Diagnostic Note |
|---|---|---|---|
| FR Wheel Speed | Front wheel speed sensor RH reading/ Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) | Vehicle stopped: 0 km/h (0 mph) | When driving at constant speed: No large fluctuations |
| FL Wheel Speed | Front wheel speed sensor LH reading/ Min.: 0 km/h (0 mph), Max.: 326 km/h (202 mph) | Vehicle stopped: 0 km/h (0 mph) | When driving at constant speed: No large fluctuations |
Check the speed value output from the speed sensor displayed on the GTS.
Tech Tips
Factors that affect the indicated vehicle speed include tire size, tire pressure, 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 Click here.
| OK |
|---|
| The speed value output from the speed sensor displayed on the GTS is similar to the speed indicated on the speedometer. |
| NG |
|
CHECK FRONT SPEED SENSOR INSTALLATION Click here |
| OK |
|
PERFORM TEST MODE INSPECTION (SIGNAL CHECK)
Turn the ignition switch off.
Perform the sensor check using the Test Mode procedure Click here.
| OK |
|---|
| No Test Mode DTCs are output. |
| NG |
|
CHECK FRONT SPEED SENSOR INSTALLATION Click here |
| OK |
|
RECONFIRM DTC
Turn the ignition switch off.
Clear the DTCs Click here.
Turn the ignition switch off.
Start the engine.
Drive the vehicle at a speed of 54 km/h (34 mph) or more for at least 120 seconds.
Check if the same DTC is output Click here.
| Result | ||||||
|---|---|---|---|---|---|---|
|
Tech Tips
If troubleshooting has been carried out according to Problem Symptoms Table, refer back to the table and proceed to the next step Click here.
| A |
|
USE SIMULATION METHOD TO CHECK Click here |
| B |
|
REPLACE FRONT SPEED SENSOR Click here |
CHECK FRONT SPEED SENSOR INSTALLATION
| *a | Normal |
| *b | Abnormal |
| *c | Clearance |
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. |
| NG |
|
INSTALL FRONT SPEED SENSOR CORRECTLY Click here |
| OK |
|
CHECK FRONT SPEED SENSOR AND SENSOR ROTOR
Remove the front speed sensor and the component with the sensor rotor (See page for speed sensor, Click here for sensor rotor).
Check the speed sensor tip and speed sensor rotor.
| OK |
|---|
| No scratches, oil, or foreign matter on the sensor tip and rotor. |
Note
If no damage to the speed sensor tip is found during this inspection, do not replace the speed sensor.
If there are any ferrous metal filings stuck to the rotor, this will result in a malfunction, so confirm that the rotor is not contaminated with foreign matter before replacing the sensor.
Check the speed sensor signal after cleaning or replacement Click here.
| NG |
|
CLEAN OR REPLACE FRONT SPEED SENSOR OR COMPONENT WITH SENSOR ROTOR |
| OK |
|
CHECK HARNESS AND CONNECTOR (BRAKE ACTUATOR ASSEMBLY - FRONT SPEED SENSOR)
Install the front speed sensor and the component with the sensor rotor.
Make sure that there is no looseness at the locking part and the connecting part of the connectors.
Disconnect the A78 (for CVT) or A79 (except CVT) skid control ECU (brake actuator assembly) connector and A31 or A32 front speed sensor connector.
Measure the resistance according to the value(s) in the table below.
| Standard Resistance (for CVT) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||
|
| Standard Resistance (except CVT) | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
|||||||||||||||
|
| NG |
|
REPAIR OR REPLACE HARNESS OR CONNECTOR |
| OK |
|
RECONFIRM DTC
Reconnect the A78 (for CVT) or A79 (except CVT) skid control ECU (brake actuator assembly) connector and A31 or A32 front speed sensor connector.
Clear the DTCs Click here
Turn the ignition switch off.
Start the engine.
Drive the vehicle at a speed of 54 km/h (34 mph) or more for at least 120 seconds.
Check if the same DTC is output Click here.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| B |
|
USE SIMULATION METHOD TO CHECK Click here |
| A |
|
REPLACE FRONT SPEED SENSOR
Turn the ignition switch off.
Replace the front speed sensor Click here.
Note
Check the speed sensor signal after replacement Click here.
| NEXT |
|
RECONFIRM DTC
Clear the DTCs Click here.
Turn the ignition switch off.
Start the engine.
Drive the vehicle at a speed of 54 km/h (34 mph) or more for at least 120 seconds.
Check if the same DTC is output Click here.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| B |
|
END |
| A |
|
REPLACE FRONT AXLE HUB SUB-ASSEMBLY
Turn the ignition switch off.
Replace the front speed sensor rotor (front axle hub sub-assembly) Click here.
Tech Tips
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 the front axle hub sub-assembly.
Note
Check the speed sensor signal after replacement Click here.
| NEXT |
|
RECONFIRM DTC
Clear the DTCs Click here.
Turn the ignition switch off.
Start the engine.
Drive the vehicle at a speed of 54 km/h (34 mph) or more for at least 120 seconds.
Check if the same DTC is output Click here.
| Result | ||||||
|---|---|---|---|---|---|---|
|
| A |
|
END |
| B |
|
REPLACE BRAKE ACTUATOR ASSEMBLY Click here |