Kawasaki J300 - Service manual > ECU

ECU Removal

NOTICE Never drop the ECU especially on a hard surface.

Such a shock to the ECU can damage it.


ECU Installation

ECU Power Supply Inspection


ECU Grounding Continuity Inspection
  (I) G/P leads (ECU terminal 9 [C] or 10 [D]) ←→ Battery (-) Terminal
  (II) Engine Ground ←→ Battery (-) Terminal


 Both: about 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.




Special Tool - Needle Adapter Set: 57001-1457

ECU Power Supply Inspection
  Digital Meter (+) → Terminal 1 (BK) [C]
  Digital Meter (-) → Battery (-) Terminal
  Digital Meter (+) → Terminal 7 (R/W) [D]
  Digital Meter (-) → Battery (-) Terminal
 Ignition Switch OFF:
  Terminal 1 (BK): 0 V
  Terminal 7 (R/W): Battery Voltage
 Ignition Switch ON:
  All: Battery Voltage

If the reading is out of the specification, check the following.

Ignition Fuse 15 A (see Fuse Inspection in the Electrical System chapter)
Charging/ECU Fuse 30 A (see Fuse Inspection in the Electrical System chapter)
ECU Relay (see Relay Circuit Inspection in the Electrical System chapter)
Power Source Wiring (see wiring diagram in this section)

ECU Power Source Circuit


  1. ECU
  2. Engine Stop Switch
  3. Fuse Box
  4. Ignition Fuse 15 A
  5. Charging/ECU Fuse 30 A
  6. Ignition Switch
  7. Side Stand Switch
  8. Battery
  9. Engine Ground
  10. Frame Ground 1
  11. ECU Relay

DFI Power Source

ECU Fuse Removal

ECU Fuse Installation

If a fuse fails during operation, inspect the DFI system to determine the cause, and then replace it with a new fuse of proper amperage.

ECU Fuse Inspection

ECU Relay Removal/Installation

DFI Power Source

ECU Relay Inspection

See also:

 Kawasaki J300 - Service manual > Crankshaft Sensor (Service Code 66)

The crankshaft sensor has no power source, and when the engine stops, the crankshaft sensor generates no signals. Crankshaft Sensor Removal/Installation Refer to the Crankshaft Sensor Removal/Installation in the Electrical System chapter.

 Kawasaki J300 - Service manual > Fuel Line

Fuel Pressure Inspection NOTE Be sure the battery is fully charged.   Remove the fuel hose (see Fuel Hose Replacement in the Periodic Maintenance chapter). Be sure to place a piece of cloth around the fuel outlet pipe of the fuel pump and the fuel pipe of the intake manifold.