Mitsubishi 3000GT Service Manual page 217

IGNITION SWITCH-ST AND PARK/NEUTRAL POSITION SWITCH (PNP SWITCH)
OPERATION
The ignition switch-ST inputs a high signal to the engine control module while the engine is cranking.
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The engine control module provides fuel injection control, etc., at engine startup based on this signal.
When the ignition switch is set to START, the battery voltage at cranking is applied through the
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ignition switch and park/neutral position switch to the engine control module, which detects that the
engine is cranking.
In case the selector lever is in a position other than the P/N range, the battery voltage is not applied
to the engine control module.
The park/neutral position switch converts the selector lever position (whether it is at the P/N range
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or at others) into high/low voltage and inputs it to the engine control module, which then controls
the idle air control motor based on this signal.
The battery voltage in the engine control module is applied through a resistor to the park/neutral
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position switch. When the selector lever is set to the P/N range, continuity is produced between
the park/neutral position switch terminal of the engine control module and ground through the starter
motor, thereby making the terminal voltage go low.
TROUBLESHOOTING HINTS
If the park/neutral position switch harness and individual part checked good but the park/neutral position
switch output is abnormal, poorly adjusted control cable is suspected.
MULTIPORT
On-Vehicle Inspection of MFI
FUEL INJECTION - Components
A Equipment
side connector
Starter S Control
terminal
Engine control module connector
Ignition switch (ST)
Park/Neutral 1
position
switch
8
P
relay
, c o n t r o l
A Harness side
connector
m o d u l e /