Diagnostics - Subaru Legacy Reference Booklet

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A N
I N T R O D U C T I O N TO
A B S
5.3
SYSTEM DIAGNOSIS
The ABS 5.3 system has extensive self-
diagnostic capabilities. When the ignition
switch is turned from "Off" to "On," the
ABS system performs an electrical self-
check and illuminates the ABS warning
light for 1 1/2 seconds. If there are no
electrical problems, the system then turns
the light off.
ABS Warning Light
The ABS 5.3 system performs a second
check when vehicle speed reaches 3 mph
(if the brake has not been applied) or 8
mph (if the brake has been applied).
During this second self-check, the ABS
system operates its motor pump for 0.2 sec-
ond and exercises the solenoids.
If the ABS control unit does not detect any
problems it keeps the ABS warning light
off. If the control unit does find a prob-
lem, it turns the ABS warning light on and
stores one or more trouble codes. The ABS
system then remains passive even if a
wheel begins to lock up.
If the problem involves one of the wheel
speed sensors, with the ABS 5.3i, the sys-
tem waits until the next ignition cycle
before turning the ABS warning light on.
If, at the next ignition cycle, the ABS sys-
tem sees the same wheel speed sensor
problem again, it turns on the ABS warning
light and the system stays passive,
Otherwise, the ABS system assumes there
is no problem.
New Select Monitor
-
"Each System
Check" Selected
If a vehicle with an ABS 5.3 or 5.3i system
has an ABS warning light that stays on,
you can use the New Select Monitor to
read its trouble codes. Simply plug in the
New Select Monitor, turn the ignition
switch to "On," and select "Each System
Check" from the main menu.
New Select Monitor
-
"ABSRCS" Selected
Next, select "ABS/TCS."
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