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.
If some signal voltage
stays in abnormal voltage range, the time is counted
seperately.
And if the monitored
time exceeds the specified min. fault duration, failure is
detected.
The monitoring starts
1sec after Power Up.
Item
|
Detecting
Condition
|
Possible cause
|
DTC
Strategy
|
|
| •
|
Open or short of steering wheel sensor
circuit |
| •
|
Faulty steering wheel
sensor | |
Enable
Conditions
|
| •
|
When Vsas > 4.2±0.1V or Vsas <
1.2±0.1V or
2.1±0.1V < Vsas < 2.9±0.1V
continue 1sec.
- The monitoring starts 1sec after Power
Up.
※ Vsas : Voltage of the steering angle
sensor. | |
Fail
Safe
|
| •
|
Inhibit the ESC control and allow the
ABS/EBD control. |
| •
|
The ESC warning lamp is
activated. | |
| 1. |
Connect scantool to Data Link
Connector(DLC). |
| 2. |
Ignition "ON" & Engine
"ON". |
| 3. |
Turn the steering wheel to the left or
right. |
| 4. |
Monitor the "STEERING ANGLE SENSOR" parameters
on the Scantool.
Specification
: If the parameters are changed
according to wheel position during steering the wheel, it is
normal condition.
|
|
| 5. |
Whenever steering wheel is turned, is the
steering sensor's scantool data changed?
|
|
▶ Fault is
intermittent caused by poor connection in steering 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.
|
|
|
▶ 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?
|
|
▶ Repair as
necessary and then go to "Verification Of Vehicle Repair"
procedure.
|
|
|
▶ Go to
"Power Circuit Inspection"
procedure.
|
|
Open or Short Check
| 1. |
Ignition "ON" & Engine
"OFF". |
| 2. |
Measure voltage between power terminal of the
steering angle sensor harness connector and chassis
ground.
Specification
: Approx. 12V
| |
| 3. |
Is the measured value within
specifications?
|
|
▶ Go to
"Ground Circuit Inspection" procedure.
|
|
|
▶ Repair
open or short in power circuit between steering angle sensor
harness connector and HECU 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
properoperation.
If problem is
corrected, replace HECU and then go to "Verification Of
Vehicle Repair"
procedure.
|
|
| Ground Circuit
Inspection |
Open or Short Check
| 1. |
Ignition "OFF" & Engine
"OFF". |
| 2. |
Disconnect steering angle sensor
connector. |
| 3. |
Measure resistance between ground terminal of
the steering angle sensor harness connector and chassis
ground.
Specification
: Approx. below 1Ω
| |
| 4. |
Is the measured value within
specifications?
|
|
▶ Go to
"Signal Circuit Inspection" procedure.
|
|
|
▶ Repair
open or short in ground circuit between steering angle sensor
harness connector and HECU harness connector and then, go to
"Verification Of Vehicle Repair"
procedure.
|
|
| Signal Circuit
Inspection |
Open or Short Check
| 1. |
Ignition "ON" & Engine
"OFF". |
| 2. |
Measure voltage between signal terminal of the
HECU harness connector and chassis ground.
Specification
:
HIGH : 2.9±0.1V ~ 4.4±0.1V
LOW : 1.2±0.1V ~
2.1±0.1V
| |
| 3. |
Is the measured value within
specifications?
|
|
▶
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.
|
|
|
▶ Repair
open or short in signal circuit between the steering angle
sensor harness connector and HECU harness connector and then,
go to "Verification Of Vehicle Repair"
procedure.
▶ If there is no problem
in signal circuit, go to "Component Inspection"
procedure.
|
|
Open or Short Check
| 1. |
Ignition "ON" & Engine
"OFF". |
| 2. |
Measure voltage between signal terminal of the
steering angle sensor harness connector and chassis
ground.
Specification
:
HIGH : 2.9±0.1V ~ 4.4±0.1V
LOW : 1.2±0.1V ~
2.1±0.1V
| |
| 3. |
Is the measured value within
specifications?
|
|
▶ Fault is
intermittent caused by poor connection in steering sensor
harness and/or HECU's connector.
Go
to "Verification Of Vehicle Repair"
procedure.
|
|
|
▶
Substitute with a known-good steering angle sensor and check
for proper operation
If problem is
corrected, replace steering angle 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 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. |
Using a scantool, Check DTC
present. |
| 5. |
Are any DTCs present ?
|
|
▶ Go to the
applicable troubleshooting procedure.
|
|
|
▶ System
performing to specification at this
time.
|
|
