Replace it if necessary.

Inner Tube Inspection
Spring Tension InspectionWashing Your Motorcycle
Rinse your bike with cold water from
a garden hose to remove any loose
dirt.
Mix a mild neutral detergent (designed
for motorcycles or automobiles)
and water in a bucket. Use
a soft cloth or sponge to wash your
motorcycle. If needed, use a mild degreaser
to remove any oil or greas ...
Caliper Fluid Seal Damage
The fluid seal (piston seal) [A] is placed around the piston
to maintain clearance between the pad and the disc. If
the seal is in a poor condition, it could lead the pad to wear
excessively or the brake to drag, which may cause the temperature
of the discs or the brake fluid to increase.
Re ...
ESD (Electronic Steering Damper) ECU Error (Service Code E3b, ZX1000JD/KD)
If this service code appears, check that the following parts
are correctly.
Crankshaft Sensor
Gear Position Switch
Starter Lockout Switch
Main Throttle Sensor
Rear Wheel Rotation Sensor
If these parts are normal, check the ESD ECU for its
ground and power supply (see ESD ECU Power Supply
...