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ELECTRIC POWER STEERING (EPS)
GENERAL TROUBLESHOOTING INFORMATION
EPS INDICATOR
Under normal conditions,
the EPS
indicator comes on when
the
ignition switch is turned
to ON position,
then goes off after
the engine is started.
This
indicates that the
LED
and its circuit are
operating
correctly.
If there
is
any
trouble
in
the
system after
the
engine is started,
the EPS
indicator will stay on. (When OTe 22
(NO
WRITING
THE TORGUE
SENSOR NEUTRAL
POSITION)
is
detected
by
the
control unit
the EPS
indicator will
blink.
)
When the EPS indicator light comes on, the control unit
memorizes the
OTe.
The
control
unit
wil
' stop
the
EPS system after
the engine starts again, but it keeps the
EPS indicator
on.
When OTe 23
(TORQUE
SENSOR PROBLEM) is stored in
the control
unit,
the EPS
indicator will stay on until the OTC is
erased.
When a problem is detected and
the EPS
indicator
comes on,
there
are cases when the indicator stays on until the ignition
switch
is
turned
OFF, and cases when the indicator goes off automatically when the system returns to
normal.
DIAGNOSTIC TROUBLE CODE (DTC)
The OTCs
are memorized
in
the
EEPROM
(nonvolatile
memory) therefore the memorized
OTCs cannot be erased
by
dis-
con
necting
the battery. Perform the specified procedures
to
clear OTCs (page 25-11).
SELF DIAGNOSIS (DTC)
Self-diagnosis can be classified into three categories:
-
Initial
diagnosis:
performed
right after
the engine starts and
until the
EPS indicator goes off.
-
Regular diagnosis: performed right after the initial diagnosis until
the
ignition switch
is
turned
OFF.
-
Revest:
The EPS
indicator turns on when the OTC is set.
The EPS
indicator will turn off after the vehicle
has recovered
from the fail-safe condition, but the
OTC
will be stored
in the
EPS
ECU.
There was a temporary problem, but the system
is now fully operational.
The
EPS ECU performs the following functions when a
problem
is detected
by
self-diagnosis:
1.
Turns
on the EPS indicator.
2. Memorizes the OTC.
3. Stops power assist and manual steering operation begins or
reduce
the steering assist power.
EPS INDICATOR BLINK PATTERN
•
If the HOS pocket tester is not available, DTC can be
read from the EPS ECU
memory by the
EPS
indicator blink pattern.
•
The number of EPS indicator
blinks
is
the
equivalent
to
the
main
code of
the OTC
(the sub code cannot be displayed
by
the EPS indicator).
•
When the EPS ECU stores more than one DTC, the
EPS indicator
will indicate
them
by blinking in the order from the
lower number to highest number.
-
@OFF
----
25-8
1
3 sec
13 sec
..
-
_
..
_
..
_.
1
0.5
so<
f-
/:
0.3
sec
0.3
sec
0.5
sec! 13sec
.L..
.
2
DTC code =
12
Problem code
Example: one long blink and
two short blinks DTC code
=
12
[
0.3
sec
26 sec
-
.....
.
..
.
.
. L..
.
.
.....
...
.
L..
..
Pattern
DTe
code", 21
Repeat
ed
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