If the connector is clogged with mud or dust, blow it off with compressed air.
If the terminals of the main harness connectors are damaged, replace the main harness.
If the terminals of the ECU connectors are damaged, replace the ECU.

Gray Connector [A]

Special Tool - Hand Tester: 57001-1394
ECU Grounding Inspection
Connections:
(I) BK/Y leads (ECU terminal 40, 73 or 74) ←→ Battery (–) Terminal
(II) Engine Ground ←→ Battery (–) Terminal
Criteria: Both: 0 Ω
If no continuity, check the connectors, the engine ground lead, or main harness, and repair or replace them if necessary.
If the wiring is good, check the power source voltage of the ECU.

NOTE
Be sure the battery is fully charged.
Special Tool - Needle Adapter Set: 57001-1457
ECU Power Supply Inspection Connections:
(I) Digital Meter (+) → Terminal 41 (W/BK)
Digital Meter (–) → Battery (–) terminal
(II) Digital Meter (+) → Terminal 53 (BR/W)
Digital Meter (–) → Battery (–) terminal
(III) Digital Meter (+) → Terminal 54 (W/BK)
Digital Meter (–) → Battery (–) terminal
Ignition Switch OFF:
Terminal 41 (W/BK): Battery Voltage
Terminal 53 (BR/W): 0 V
Terminal 54 (W/BK): Battery Voltage
Ignition Switch ON:
All: Battery Voltage
If the reading is out of the specification, check the following.
Main Fuse 30 A (see Fuse Inspection in the Electrical System chapter)
ECU Fuse 15 A (see Fuse Inspection in the Electrical System chapter)
ECU Main Relay (see Relay Circuit Inspection in the Electrical System chapter)
Power Source Wiring (see wiring diagram in this section)
If the fuse, wiring and relay are good, replace the ECU (see ECU Removal/Installation).
ECU Removal
ECU Power Source CircuitImmobilizer System (Equipped Models)
This motorcycle is equipped with an immobilizer system to protect the
motorcycle from theft. This
system provides a theft proof device by means of matching a code between the
inbuilt key transponder
and ECU. If the code does notmatch, ignition system, injectors, subthrottle
valve actuator an ...
ECU Identification
Most countries have their own regulations, so each ECU
has different characteristic. So, do not confuse ECU with
each other and use only the ECU for your model. Otherwise,
the motorcycle can not clear the regulation.
ECU Identification
ZX1000JB/KB
ZX1000JC /KC
...
Bolts, Nuts and Fasteners Tightness Inspection
Check the tightness of the bolts and nuts listed here. Also,
check to see that each cotter pin is in place and in good
condition.
NOTE
For the engine fasteners, check the tightness of them
when the engine is cold (at room temperature).
If there are loose fasteners, retighten them to ...