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 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).
Item
|
Detecting
Condition
|
Possible cause
|
DTC
Strategy
|
|
| •
|
Open or short of Wheel speed sensor
circuit |
| •
|
Faulty Wheel speed
sensor | |
Enable
Conditions
|
| •
|
When the sensor signal current is
continuously out of the specified range of 4 mA ± 10% ~ 22 mA
± 10% for 140msec. | |
Fail
Safe
|
| 1. |
Inhibit the ABS/ESC control, allow the
EBD control. The ABS/ESC warning lamps are activated, the EBD
warning lamp is not
activated. |
| 2. |
The ABS/EBD/ESC functions are inhibited.
The ABS/EBD/
ESC warning lamps are
activated. | |
Sensor Type
|
Output Voltage
|
Tooth Count
|
Airgap
|
HIGH
|
LOW
|
Active
Type
|
1.4V
|
0.7V
|
52
|
0.4~1.5mm
|
| 1. |
Ignition "ON" & Engine
"ON". |
| 2. |
Connect scantool 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
Scantool.
Specification
: Compare with other parameters
related to wheel speed sensor.
If it is the same as other parameters,
it is in normal condition.
|
|
| 5. |
Is parameter displayed within
specifications?
|
|
▶ 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.
|
|
|
▶ 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
wheel speed sensor harness connector and chassis
ground.
Specification
: Approx. B+
| |
| 3. |
Is the measured value within
specifications?
|
|
▶ Go to
"Signal Circuit Inspection" procedure.
|
|
|
▶ 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
| 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 osciloscope.
Specification
:
High : 1.18~1.68V
Low : 0.59~0.84V
|
Normal Waveform
|
| 5. |
Is the measured waveform 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 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.
|
|
Wheel Speed Sensor Circuit Check
| 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
osciloscope.
Specification
:
High : 1.18~1.68V
Low : 0.59~0.84V
|
Normal Waveform
|
| 5. |
Is the measured waveform within
specifications?
|
|
▶ Fault is
intermittent caused by poor connection in wheel speed sensor
harness.
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.
|
|
| 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. (Start and drive vehicle in gear
and maintain vehicle speed at or above 10kmh.
(6.2mph)) |
| 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.
|
|
