Brake System

Component Location





General Description

The Steering wheel angle sensor uses two sensors ( A-sensor and B-sensor ) to determine the direction of the rotation. The main components of each sensor are LED, photo transistor and slit plate.The slit plate, which has 45 holes, is installed between LED and photo transistor, and generates signals if slit plate rotates according to the steering wheel rotation.The sensor signals are generated by photo transistor which is driven whenever the light passes through the holes. The HECU detects operating speed and direction of the steering wheel by this input signal, and the signal is used to input signal for anti-roll control.

DTC Description

This monitoring function monitors the changing point of N-signal with measured steering angle from ST1 and ST2. If N-signal changing point differs more than predefined degree, the failure is detected. If there is no variation of the steering wheel angle for predefined time ECU detect the failure.

DTC Detecting Condition





Terminal and Connector Inspection

1. Many malfunctions in the electrical system are caused by poor harness(es) and terminal conditions. 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 "Signal Circuit Inspection" procedure.

Signal Circuit Inspection

1. Ignition "ON" & Engine "ON".
2. Turn the steering wheel to the left or right.
3. Measure signal waveform between terminal "3, 4, 5" of the steering wheel angle sensor harness connector and chassis ground.

Specification :
HIGH : 2.9 ± 0.1 V ~ 4.4 ± 0.1 V
LOW : 1.2 ± 0.1 V ~ 2.1 ± 0.1 V









4. Is the measured signal waveform within specifications?
YES
> Go to "Component Inspection" procedure.
NO
> Check for open or short in steering wheel angle sensor harness between terminal "3, 4, 5" of the steering wheel angle sensorr harness connector and terminal "8, 40, 39" of the HECU harness connector. Repair as necessary and then go to "Verification Of Vehicle Repair" procedure.
> If STN signal is LOW when the steering wheel is in center position, Check for improper installation of steering angle sensor. Repair as necessary and then go to "Verification Of Vehicle Repair" procedure.
> If OK, substitute with a known-good steering wheel angle sensor and check for proper operation. If problem is corrected, replace steering wheel angle sensor and then go to "Verification Of Vehicle Repair" procedure.

Component Inspection

1. Ignition "OFF".
2. Engine "ON".
3. Does warning lamp remain On?
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
> Fault is intermittent caused by open or short of steering wheel angle sensor harness and/or faulty steering wheel angle sensor or was repaired and HECU memory was not cleared. Go to the applicable troubleshooting procedure.

Verification Of Vehicle Repair

After a repair, it is essential to verify that the fault has been corrected.
1. Connect scantool and select "Diagnostic Trouble Codes (DTCs)" mode.
2. Using a scantool, Clear DTC.
3. Operate the vehicle within DTC Detecting Condition in General Information.
4. Are any DTCs present ?
YES
> Go to the applicable troubleshooting procedure.
NO
> System performing to specification at this time.