Perkins 1106D Troubleshooting Manual page 145

KENR6201-01
Some applications may be equipped with an
engine protection shutdown system or an idle timer
shutdown system that interrupts electrical power
to the keyswitch. The engine protection shutdown
system can be an aftermarket device and the idle
timer shutdown system can be external to the ECM.
Some of these systems will not supply power to the
ECM until one of the following conditions is met:
• The engine is cranked.
• The engine oil pressure achieves acceptable limits.
•
An override button is pressed.
These devices may be the cause of intermittent
power to the ECM. These devices may also shut
down the engine.
Usually, battery power to the diagnostic connector
is available and the battery power to the data link
connector is independent of the keyswitch. Therefore,
although it is possible to power up the electronic
service tool, there may be no communication with
the engine ECM. The engine ECM requires the
keyswitch to be in the ON position in order to maintain
communications. The ECM may power down a short
time after connecting the electronic service tool if the
keyswitch is in the OFF position. This is normal.
For intermittent faults such as intermittent shutdowns
that could be caused by the wiring on the application,
temporarily bypassing the wiring on the application
may be an effective means of determining the root
cause. If the symptoms disappear with the bypass
wiring, the wiring on the application is the cause of
the fault. A means of bypassing the wiring on the
application is explained in this test procedure. This
is especially important for applications that do not
provide dedicated circuits for the unswitched battery
and the connections for the keyswitch.
This document is printed from SPI². Not for RESALE
145
Troubleshooting Section