ELECTRICAL SYSTEMS
8.112004 Four Stroke PWC Service Manual
System Interface Box (SIFB)
Theprimary function of the SIFB is to power--down the ignition system in the event that the lanyard is left inserted
in the stop switch for more than two minutes. Without the SIFB, the ignition system would remain powered--up
by the battery, and the battery would completely discharge.
Asecondary function of the SIFB is to convert the reverse switch signal so the ECU can interpret the signal when
thereverse switch is closed, thereby limiting engine RPM.
How It works
TheSIFB will disconnect the ECU ignition circuit and go
into the “sleep” mode in the event that the lanyard is left
installed in the stop switch for more than two minutes. This
also holds true whenever the operator pushes the stop but-
tonmomentarily while the engine is running.
In theevent that the operator removes the lanyard from the
stop switch while the engine is running, the SIFB does
nothing.
To power--up the ECU after the SIFB has entered the
“sleep” mode, the operator must re--insert (if removed) the
lanyard into the stop switch, and press the start button.
NOTE: The SIFB remains in the mode in which it
was put into by the operator’s last action. For ex-
ample, the SIFB will allow the ECU to power-- up im-
mediately when the lanyard isinstalled if the opera-
tor’slast action was removing the lanyard to kill the
engine.
Conversely, if the operator’s last action was leaving
thelanyard in the stop switch for more than two
minutes or stopping the engine by pushing the stop
button, the ECU will not power--up until the SIFB
“sees” a start signal generated by the operator
pushing the start button.
SIFB Diagnostics Mode
There will be situations where a user will want to defeat the sleep mode function of the SIFB. One such situation
is when a technician is connected to the ECU with the Digital Wrencht diagnostic software program.
To enter the SIFB diagnostic mode, follow these steps:
1. Insert the lanyard into the stop switch, and start the engine. Stop the engine by removing the lanyard.
2. Wait for15 seconds, then re--insert the lanyard. Quickly push the STOP button three times within the first
threeseconds, then tap the START button.
TheSIFBisnow in the diagnostics mode. Power will be supplied to the ECU for as long as the lanyard remains
installed.
To exit the diagnostics mode, remove the safety lanyard from the STOP switch and wait for at least 15 seconds.
NOTE: To verify the ignition system is powered--up after inserting the lanyard into the stop switch,
move thethrottle flipper from full closed to full open while the engine is off. The throttle plate can
always be heard moving with the flipper movement when the ignition system has power.
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