Replace the KIBS hydraulic unit or main harness if either of the terminals are cracked, bent, or otherwise damaged.
If the KIBS hydraulic unit connector is clogged with mud or dust, blow it off with compressed air.
Replace the KIBS hydraulic unit if any of them are cracked, or otherwise damaged.

KIBS Hydraulic Unit Installation
Front Wheel Rotation Sensor RemovalPiston Wear Inspection
Measure the outside diameter [A] of each piston 5 mm
(0.20 in.) [B] up from the bottom of the piston at a right
angle to the direction of the piston pin.
If the measurement is under service limit, replace the piston.
Piston Diameter
Standard: 75.959 75.974 mm
(2.9905 2.9911 in.)
...
Tire Wear, Damage
As the tire tread wears down, the tire
becomes more susceptible to puncture
and failure. An accepted estimate is
that 90% of all tire failures occur during
the last 10% of tread life (90% worn).
So it is false economy and unsafe to
use the tires until they are bald
In accordance with the ...
Relay Circuit Inspection
Remove the relay box (see Relay Box Removal).
Check conductivity of the following numbered terminals
by connecting the hand tester and one 12 V battery to the
relay box as shown in the figure (see Relay Box Internal
Circuit in this section).
If the tester does not read as specified, re ...