4.
Monitor the "WHEEL SPD SNSOR-FL, FR, RL, RR" parameter on the Scantool.
Specification : Compare with another parameters related to wheel speed sensor. If it is the same as another parameters, it is in normal condition.
The wheel speed sensor is the essential component the ABS ECU uses to calculate vehicle speed and to determine whether wheel lock occurs. For example, rear wheel speed signal is used as a referecnce value, for vehicle speed, in front wheel drive vehicles, and if a difference between front and rear wheel speed occurs, then ABS control is performed. Wheel speed sensor is active hall-sensor type.
The ABS ECU monitors the wheel speed sensor signal continuously.
If power supply of the WSS input amplifier is not normal or the ABS control cycle is continued abnormally, if the exact fault location among 4 WSS can not be determined, This code is set.
Item | Detecting Condition | Possible cause | |
Case 1 | DTC Strategy | ● Voltage motorning | ● Improper installation of wheel speed sensor ● Abnormal Rotor and wheel bearing ● Faulty Wheel speed sensor |
Monitoring Period | ● Continuous (If no under voltage, no BLS, no BLS failure is detected) | ||
Enable Conditions | ● When WSS low voltage is detected. | ||
Fail Safe | ● Wheel speed sensor signals are not reliable. | ||
Case 2 | DTC Strategy | ● Signal motorning | |
Monitoring Period | ● Continous | ||
Enable Conditions | ● The monitoring reports a failure if the ABS target slip is exceeded for a time period ＞= 10 s at one or more wheels. - If the driver brakes or the velocity is lower than 50 km/h(31 MPH) the detection time is increased to 60 s. | ||
Fail Safe | ● Reduced function of the ESP system | ||
- Refer to case 3, 4 of C1202.
Sensor Type | Output Voltage | Air Gap | |
HIGH | LOW | ||
Active Type | 1.05V | 0.525V | 0.7 mm - FRONT 0.5 mm - REAR |
Ignition "ON" ＆ Engine "ON".
Connect scantool to Data Link Connector(DLC).
Start and drive vehicle in gear and maintain vehicle speed at or above 50 km/h(31 mph)
Monitor the "WHEEL SPD SNSOR-FL, FR, RL, RR" parameter on the Scantool.
Specification : Compare with another parameters related to wheel speed sensor. If it is the same as another parameters, it is in normal condition.
Is parameter displayed within specifications?
▶ Fault is intermittent caused by poor connection in wheel speed sensor harness, Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage. Repair or replace as necessary and then go to "Verification Of Vehicle Repair" procedure..
▶ Go to "Component Inspection" Procedure.
Lift the vehicle.
Ignition "ON" ＆ Engine "OFF".
Turn the wheel by hand.
Measure waveform between terminal "1" of the wheel speed sensor harness connector and chassis ground.
Specification :
Approx. High : 1.05 V , Low : 0.525 V
Compare waveforms of all wheel speed sensors.
If they have same waveform, it is in normal condition.
Is the measured waveform within specifications?
▶ Fault is intermittent caused by poor connection in wheel speed sensor harness. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage and external noise, an interference between harnesses. Repair or replace as necessary and then go to "Verification of Vehicle Repair" procedure.
▶ If OK, Substitute with a known-good HECU and check for proper operation.
If problem is corrected, replace HECU and then go to "Verification of Vehicle Repair" procedure.
▶ Check following point at wheel speed sensor which has abnormal waveform.
▶ Check for improper installation of wheel speed sensor. If NG, repair as necessary and then go to "Verification Of Vehicle Repair" procedure.
▶ Check for damage of rotor teeth or wheel bearing. If NG, repair as necessary and then go to "Verification Of Vehicle Repair" procedure.
▶ Substitute with a known-good Wheel speed sensor and check for proper operation. If problem is corrected, replace Wheel speed sensor and then go to "Verification Of Vehicle Repair" procedure.
After a repair, it is essential to verify that the fault has been corrected.
Connect scantool and select "Diagnostic Trouble Codes(DTCs)" mode
Using a scantool, Clear DTC.
Operate the vehicle within DTC Detecting Condition in General Information. (Start and drive vehicle in gear and maintain vehicle speed at or above 50km/h. (31.1mph)
Are any DTCs present ?
▶ Go to the applicable troubleshooting procedure.
▶ System performing to specification at this time.
