C1206

DTC C1200 FL WHEEL SPEED SENSOR-OPEN/SHORT
DTC C1203 FR WHEEL SPEED SENSOR-OPEN/SHORT
DTC C1206 RL WHEEL SPEED SENSOR-OPEN/SHORT
DTC C1209 RR WHEEL SPEED SENSOR-OPEN/SHORT

COMPONENT LOCATION:

GENERAL DESCRIPTION

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 reference 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 and good at temperature and noise characteristic A digital wave is produced as the tone wheel rotates according to the hall sensor principle. Frequency of duty wave is changed in proportion to rotation of tone wheel and HECU calculates vehicle speed by this frequency.

DTC DESCRIPTION

The ABS ECU monitors the wheel speed sensor circuit continuously. A direct current is supplied in the wheel-speed sensor by a power source in the input amplifier of the control unit. If the WSS circuit is broken, in that case a fault is detected by detecting abnormal input current. HECU cuts off the voltage supply to wheel sensor channel which had a fault to prevent vehicle's damage due to super heated harness. If one or more defects has detected, DTC code of defected wheel will be stored. Mutual short between sensors is detected by executing self diagnosis successively at corresponding wheel when ignition ON. Warning lamp is turned OFF unless fault is detected any more when the IG KEY is turned ON again.

DTC DETECTING CONDITION

DTC DETECTING CONDITION:

MONITOR SCANTOOL DATA

1. Engine "ON".
2. Connect scan tool to Data Link Connector(DLC).
3. Start and drive vehicle in gear and maintain vehicle speed at approximately 10 km/h or more(6 mph or more)
4. Monitor the "Wheel speed sensor" parameter on the scan tool.

Specification: Approximately 10 km/h or more (6 mph or more)





5. Is parameter displayed within specifications?

YES
^ Fault is intermittent caused by poor connection in wheel speed sensor harness and/or HECU's connector or was repaired and HECU memory was not cleared. 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.

NO
^ Go to "W/Harness Inspection" procedure.

TERMINAL & CONNECTOR INSPECTION

Refer to DTC C1102. C1102

POWER SUPPLY CIRCUIT INSPECTION

1. Ignition *ON".
2. Measure voltage between terminal (front: "1", rear: "2") of the wheel speed sensor harness connector and chassis ground.

Specification: Approximately B+





3. Is the measured voltage within specifications?

YES
^ Go to "Signal Circuit Inspection" procedure.

NO
^ Check for open or short to GND in wheel speed sensor harness between terminal (front:1 ", rear:"2") of the wheel speed sensor harness connector and terminal of the HECU harness connector. Repair as necessary and then go to "Verification of vehicle Repair" procedure.
^ If OK, go to "Component inspection" procedure.





SIGNAL CIRCUIT INSPECTION

1. Lift the vehicle by lift.
2. Ignition "ON".
3. Turn the wheel with hand.
4. Measure wave between terminal of the HECU harness connector and chassis ground.

Specification: High: 1.4 V , Low: 0.7 V





5. Is the measured wave within specifications?

YES
^ Go to "Component Inspection" procedure.

NO
^ Check for open or short to GND in wheel speed sensor harness between terminal (front:"2", rear:"1") of the wheel speed sensor harness connector and terminal of the HECU harness connector. Repair as necessary and then go to "Verification of vehicle Repair" procedure.
If OK, 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.

COMPONENT INSPECTION

Refer to DTC C1101. C1101

VERIFICATION OF VEHICLE REPAIR

After a repair, it is essential to verity that the fault has been corrected.
1. Connect scan tool and select "Diagnostic Trouble Codes(DTCs)" mode
2. Using a scan tool, clear DTC.
3. Operate the vehicle within DTC Detecting Condition in General Information. (Start and drive vehicle in gear and maintain vehicle speed is approximately 10 km/h or more(6 mph or more))
4. Are any DTCs present?

YES
^ Go to the applicable troubleshooting procedure.

NO
^ System performing to specification at this time.