Kawasaki J300 - Service manual > DFI Servicing Precautions
DFI Servicing Precautions
There are a number of important precautions that should be followed servicing the DFI system.
- This DFI system is designed to be used with a 12 V sealed battery as its power source. Do not use any other battery except for a 12 V sealed battery as a power source.
- Do not reverse the battery cable connections. This will damage the ECU.
- To prevent damage to the DFI parts, do not disconnect the battery cables or any other electrical connections when the ignition switch is on, or while the engine is running.
- Take care not to short the leads that are directly connected to the battery positive (+) terminal to the chassis ground.
- When charging, remove the battery from the motorcycle.
This is to prevent ECU damage by excessive voltage.
- Whenever the DFI electrical connections are to be disconnected, first
turn off the ignition switch, and disconnect the battery (-) terminal. Do
not pull the lead, only the connector.
Conversely, make sure that all the DFI electrical connections are firmly reconnected before starting the engine.
- Connect these connectors until they click [A].
- Do not turn the ignition switch on while any of the DFI electrical connectors are disconnected. The ECU memorizes service codes.
- Do not spray water on the electrical parts, DFI parts, connectors, leads and wiring.
- If a transceiver is installed on the motorcycle, make sure that the operation of the DFI system is not influenced by electric wave radiated from the antenna. Check operation of the system with the engine at idle. Locate the antenna as far as possible away from the ECU.
- When any fuel hose is disconnected, do not turn on the ignition switch. Otherwise, the fuel pump will operate and fuel will spout from the fuel hose.
- Do not operate the fuel pump if the pump is completely dry. This is to prevent pump seizure.
- Before removing the fuel system parts, blow the outer surfaces of these parts clean with compressed air.
- When any fuel hose is disconnected, fuel may spout out by residual pressure in the fuel line. Cover the hose joint with a piece of clean cloth to prevent fuel spillage.
- When installing the fuel hoses, avoid sharp bending, kinking, flattening or twisting, and run the fuel hoses with a minimum of bending so that the fuel flow will not be obstructed.
- Run the hoses according to Cable, Wire, and Hose Routing section in the Appendix chapter.
- To prevent corrosion and deposits in the fuel system, do not add to fuel any fuel antifreeze chemicals.
- If the motorcycle is not properly handled, the high pressure inside the
fuel line can cause fuel to leak or the hose to burst. Check the fuel hose
[A] (see Fuel Hose Inspection (fuel leak, damage, installation condition) in
the Periodic Maintenance chapter).
Replace the fuel hose if any fraying, cracks or bulges are noticed.
- To maintain the correct fuel/air mixture (F/A), there must be no intake air leaks in the DFI system. Be sure to install the oil filler cap/dipstick [A] after filling the engine oil.
Troubleshooting the DFI System
When a problem occurs with DFI system, the yellow engine warning indicator light (LED) [A] blinks on to alert the rider.
And the engine warning symbol [A] and the service code (error code) [B] are displayed on the LCD by the number of two digits.
When the service code is displayed, for first ask the rider about the conditions [A] of trouble, and then start to determine the cause [B] of problem.
As a pre-diagnosis inspection, check the ECU for ground and power supply, the fuel line for no fuel leaks, and for correct pressure. The pre-diagnosis items are not indicated by the yellow engine warning indicator light (LED).
Don't rely solely on the DFI self-diagnosis function, use common sense.
Even if the repair has been done, the service codes stored in memory of the ECU are not erased to preserve the problem history. But, the service code can be erased with the specified procedures.
When the motorcycle is down, the vehicle-down sensor operates and the ECU shuts off the fuel pump relay, fuel injectors and ignition system. The ignition switch is left on.
If the starter button is pushed, the electric starter turns but the engine does not start. To start the engine again, raise the motorcycle, turn the ignition switch off, and then on.
Much of the DFI system troubleshooting work consists of confirming continuity of the wiring. The DFI parts are assembled and adjusted with precision, and it is impossible to disassemble or repair them.
- When checking the DFI parts, use a tester which can be read two decimal
place voltage or resistance.
- The DFI part connectors [A] have seals [B], including the ECU. When measuring the input or output voltage with the connector joined, use the needle adapter set [C]. Insert the needle adapter inside the seal until the needle adapter reaches the terminal.
Special Tool - Needle Adapter Set: 57001-1457
NOTICE Insert the needle adapter straight along the terminal in the connector to prevent short-circuit between terminals.
- Make sure that measuring points are correct in the connector, noting the position of the lock [D] and the lead color before measurement. Do not reverse connections of a tester.
- Be careful not to short-circuit the leads of the DFI or electrical system parts by contact between adapters.
- Turn the ignition switch on and measure the voltage with the connector joined.
NOTICE Incorrect, reverse connection or short circuit by needle adapters could damage the DFI or electrical system parts.
- After measurement, remove the needle adapters and apply silicone sealant to the seals [A] of the connector [B] for waterproofing.
Sealant - Liquid Gasket, TB1211: 56019-120
- Always check battery condition before replacing the DFI parts. A fully charged battery is a must for conducting accurate tests of the DFI system.
- Trouble may involve one or in some cases all items.
Never replace a defective part without determining what CAUSED the problem. If the problem was caused by some other item or items, they too must be repaired or replaced, or the new replacement part will soon fail again.
- Measure the coil winding resistance when the DFI part is cold (at room temperature).
- Make sure all connectors in the circuit are clean and tight, and examine
wires for signs of burning, fraying, short, etc. Deteriorated wires and bad
connections can cause reappearance of problems and unstable operation of the
If any wiring is deteriorated, replace the wiring.
- Pull each connector apart and inspect it for corrosion, dirt, and
If the connector is corroded or dirty, clean it carefully. If it is damaged, replace it. Connect the connectors securely.
- Check the wiring for continuity.
- Use the wiring diagram to find the ends of the lead which is suspected of being a problem.
- Connect a tester between the ends of the leads.
If the tester does not read about 0 Ω, the lead is defective.
Replace the lead or the main harness.
- If both ends of a harness [A] are far apart, ground [B] the one end [C], using a jumper lead [D] and check the continuity between the end [E] and the ground [F]. This enables to check a long harness for continuity. If the harness is open, repair or replace the harness.
- When checking a harness [A] for short circuit, open one end [B] and check the continuity between the other end [C] and ground [D]. If there is continuity, the harness has a short circuit to ground, and it must be repaired or replaced.
- Narrow down suspicious locations by repeating the continuity tests from
the ECU connectors.
If no abnormality is found in the wiring or connectors, the DFI parts are the next likely suspects. Check the part, starting with input and output voltages. However, there is no way to check the ECU itself.
If an abnormality is found, replace the affected DFI part.
If no abnormality is found in the wiring, connectors, and DFI parts, replace the ECU.
DFI Diagnosis Flow Chart
Inquiries to Rider
- Each rider reacts to problems in different ways, so it is important to confirm what kind of symptoms the rider has encountered.
- Try to find out exactly what problem occurred under exactly what conditions by asking the rider; knowing this information may help you reproduce the problem.
- The following sample diagnosis sheet will help prevent you from overlooking any areas, and will help you decide if it is a DFI system problem, or a general engine problem.
Sample Diagnosis Sheet
DFI System Troubleshooting Guide
- This is not an exhaustive list, giving every possible cause for each problem listed. It is meant simply as a rough guide to assist the troubleshooting for some of the more common difficulties in DFI system.
- The ECU may be involved in the DFI electrical and ignition system troubles. If these parts and circuits are checked out good, be sure to check the ECU for ground and power supply. If the ground and power supply are checked good, replace the ECU.
Engine Won't Turn Over
Poor Running at Low Speed
Poor Running or No Power at High Speed:
Kawasaki J300 - Service manual > Exploded View, DFI System/Parts Location, Specifications, Special Tools