When the vehicle is
turning with respect to a vertical axis the yaw rate sensor detects the
yaw rate electroniclly by the vibration change of plate fork inside the
yaw rate sensor.
If yaw velocity reaches
the specific velocity after it detects the vehicle' yawing, the ESC
control is reactivated.
The later G sensor
senses vehicle's lateral G. A small element inside the sensor is attached
to a deflectable leverarm by later G.
Direction and magnitude
of lateral G loaded to vehicle can be known with electrostatic capacity
changing according to lateral GG.
It interchanges signals
with HECU through extra CAN line which only used for communication between
HECU and sensor.
A failure is detected if
the Yaw rate & later G sensor message was not received or HECU detects
sensor CAN Bus off state for more than the specified failure detection
time.
The Monitoring starts
1sec after Power Up.
Item
|
Detecting
Condition
|
Possible cause
|
Case1
|
DTC
Strategy
|
| •
|
Yaw rate & later G sensor message
monitoring | |
| •
|
Faulty Yaw Rate & Lateral G
sensor |
| •
|
Open or short of Yaw Rate & Lateral
G sensor | |
Enable
Conditions
|
| •
|
In case that Yaw rate & later G
sensor message was not received for more than 500ms within
normal voltage condition.
- The Monitoring starts 1s after Power
Up. | |
Case2
|
DTC
Strategy
|
|
Enable
Conditions
|
| •
|
In case sensor CAN BUS off state
continued for more than
100ms. | |
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
"OFF". |
| 3. |
Monitor the "Lateral G Sensor, Yaw Rate
Sensor" parameter on the Scantool.
Specification
: Lateral G Sensor : approx. ± 0.0 G,
YAW Rate Sensor :approx. ± 0.0 deg/s
|
|
| 4. |
Is parameter displayed within
specifications?
|
|
▶ Fault is
intermittent caused by poor connection in Yaw Rate &
Lateral G 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
Yaw Rate & Lateral G 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 the yaw rate &
lateral G 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 proper operation.
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 yaw rate & lateral G sensor
connector. |
| 3. |
Measure resistance between ground terminal of
the yaw rate & lateral G 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 the yaw rate &
lateral G sensor harness connector and HECU harness connector
and then, go to "Verification Of Vehicle Repair"
procedure.
|
|
| Signal Circuit
Inspection |
Short Check (to ground)
| 1. |
Ignition "OFF" & Engine
"OFF". |
| 2. |
Disconnect yaw rate & lateral G sensor,
HECU connector. |
| 3. |
Measure resistance between CAN LOW terminal,
CAN HIGH terminal of the yaw rate & lateral G sensor harness
connector and chassis ground.
|
| 4. |
Is the measured value within
specifications?
|
|
▶ Go to
next procedure.
|
|
|
▶ Repair
short to ground in CAN signal circuit in case of abnormal
resistance measured and then go to "Verification Of Vehicle
Repair"
procedure.
|
|
Short Check (To Battery)
| 1. |
Ignition "ON" & Engine
"OFF". |
| 2. |
Disconnect HECU
connector. |
| 3. |
Measure voltage between CAN LOW terminal, CAN
HIGH terminal of the HECU harness connector and chassis
ground.
Specification
: Approx. 0 V
| |
| 4. |
Is the measured value within
specifications?
|
|
▶ Go to
next procedure.
|
|
|
▶ Repair
short to battery in CAN signal circuit in case of abnormal
voltage measured and then, go to "Verification Of Vehicle
Repair"
procedure.
|
|
Internal Resistance Check
| 1. |
Ignition "OFF" & Engine
"OFF". |
| 2. |
Disconnect HECU
connector. |
| 3. |
Measure resistance between CAN LOW terminal
and CAN HIGH terminal of the HECU connector.
Specification
: Approx. 120 Ω
| |
| 4. |
Is the measured value within
specifications?
|
|
▶ Go to
"Component Circuit Inspection" procedure.
|
|
|
▶
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.
|
|
| Component Circuit
Inspection |
Component Resistance Check
| 1. |
Ignition "OFF" & Engine
"OFF". |
| 2. |
Disconnect HECU
connector. |
| 3. |
Measure resistance between CAN LOW terminal
and CAN HIGH terminal of the HECU harness connector.
Specification
: Approx. 120 Ω
| |
| 4. |
Is the measured value within
specifications?
|
|
▶ Fault is
intermittent caused by poor connection in yaw rate &
lateral G sensor harness and/or HECU's
connector.
Go to "Verification Of
Vehicle Repair" procedure.
|
|
|
▶ In case
of the resistance "approx. 1Ω" : Repair mutual short in CAN
signal circuit of the yaw rate & lateral G sensor and then
go to "Verification Of Vehicle Repair"
procedure.
▶ In case of the
resistance "∞ Ω" : Repair open in CAN signal circuit of the
yaw rate & lateral G sensor and then go to "Verification
Of Vehicle Repair" procedure.
▶ If
there is no problem in CAN signal circuit, Substitute with a
known-good yaw rate & lateral G sensor and check for
proper operation.
If problem is
corrected, replace the yaw rate & lateral G 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.
|
|
