3-18 FUEL SYSTEM (DFI)
Troubleshooting the DFI System
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
Insert the needle adapter straight along the terminal
in the connector to prevent short-circuit between
Make sure that measuring points are correct in the con-
nector, 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 elec-
trical system parts by contact between adapters.
Turn the ignition switch on and measure the voltage with
the connector joined.
Incorrect, reverse connection or short circuit by
needle adapters could damage the DFI or electrical
After measurement, remove the needle adapters and ap-
ply silicone sealant to the seals [A] of the connector [B]
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.