C1203
DTC C1200 WHEEL SPEED SENSOR FRONT-LH OPEN/SHORTDTC C1203 WHEEL SPEED SENSOR FRONT-RH OPEN/SHORT
DTC C1206 WHEEL SPEED SENSOR REAR-LH OPEN/SHORT
DTC C1209 WHEEL SPEED SENSOR REAR-RH 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.
DTC DESCRIPTION
The ABS ECU monitors the wheel speed sensor circuit continuously.
If the sensor signal current is continuously out of the specified range for 140msec, then the HECU determines that the circuit is open/short, and sets this code.
Warning lamp is turned OFF unless additional faults are detected when the IG KEY is turned ON again, and wheel speed is more than 10 Km/h (6.2mph).
DTC DETECTING CONDITION:
SPECIFICATION:
SCHEMATIC DIAGRAM:
SIGNAL WAVEFORM DATA:
MONITOR SCANTOOL DATA
1. Ignition "ON" Engine "ON".
2. Connect scan tool to Data Link Connector (DLC)
3. Start and drive vehicle in gear and maintain vehicle speed at or above 10km/h. (6.2mph)
4. Monitor the "WHEEL SPEED" parameter on the scan tool.
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 "Terminal and Connector Inspection" procedure.
TERMINAL AND CONNECTOR INSPECTION
1. Many malfunctions in the electrical system are caused by poor harness (es) and terminal condition. Faults can also be caused by interference from other electrical systems, and mechanical or chemical damage.
2. Thoroughly check connectors for looseness, poor connection, bending, corrosion, contamination, deterioration, or damage.
3. Has a problem been found?
YES
Repair as necessary and then go to "Verification of Vehicle Repair" procedure.
NO
Go to "Power Circuit Inspection" procedure.
POWER CIRCUIT INSPECTION
OPEN OR SHORT CHECK
1. Ignition "ON" Engine "OFF".
2. Measure voltage between power terminal of the wheel speed sensor harness connector and chassis ground.
Specification Approximately B+
3. Is the measured value within specifications?
YES
Go to "Signal Circuit Inspection" procedure.
NO
Repair open or short in power circuit between HECU harness connector and wheel speed sensor harness connector and then go to "Verification of Vehicle Repair" procedure.
If there is no problem in Power circuit, 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.
SIGNAL CIRCUIT INSPECTION
WHEEL SPEED SENSOR CIRCUIT CHECK
1. Lift the vehicle.
2. Ignition "ON" Engine "OFF".
3. Turn the wheel by hand.
4. Measure waveform between wheel speed sensor signal terminal of the HECU harness connector and chassis ground with oscilloscope.
NORMAL WAVEFORM:
5. Is the measured waveform within specifications?
YES
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.
NO
Repair open or short in signal circuit between HECU harness connector and wheel speed sensor harness connector, and then go to "Verification of vehicle Repair" procedure.
If there is no problem in signal circuit, go to "Component Inspection" procedure.
COMPONENT INSPECTION
WHEEL SPEED SENSOR CIRCUIT CHECK
1. Lift the vehicle.
2. Ignition "ON" Engine "OFF".
3. Turn the wheel by hand.
4. Measure waveform between signal terminal of the wheel speed sensor harness connector and chassis ground with oscilloscope.
NORMAL WAVEFORM:
5. Is the measured waveform within specifications?
YES
Fault is intermittent caused by poor connection in wheel speed sensor harness.
Go to "Verification of Vehicle Repair" procedure.
NO
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.
VERIFICATION OF VEHICLE REPAIR
After a repair, it is essential to verify 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 at or above 10 km/h. (6.2 mph))
4. Using a scan tool, Check DTC present.
5. Are any DTCs present
YES
Go to the applicable troubleshooting procedure.
NO
System performing to specification at this time.