3-10 ENGINE CONTROL SYSTEM
NEUTRAL SWITCH
The neutral switch is installed on the cylinder block (starboard
side) and used to detect the shift position.
This switch is “ON” in neutral and “OFF” in forward or reverse.
Based on the switch’s shift position signal input, the ECM per-
forms the following controls:
• When the shift is in forward or reverse at the time of engine
start, the fuel injection function is cancelled.
(Start-in-gear protection. See the page 3-34.)
• When the shift is in neutral, fuel injection is controlled so that
the engine speed does not exceed 3000 r/min.
• When the shift is in neutral, if the engine speed exceeds 1000
r/min, ignition timing is fixed at BTDC 5
°.
• After shifting into forward or reverse from neutral, the IAC valve
is controlled to increase intake air for two seconds to prevent
unstable engine idle or stalling.
CTP (Closed Throttle Position) SWITCH
The CTP switch is installed on the bottom of throttle body and
used to detect whether the throttle is fully closed or not.
This switch is “ON” at closed throttle and “OFF” at any open throttle
position. Based on the switch’s throttle position signal input, the
ECM determines the control modes for various control system
(idle aire contrl, ignition timing control, etc.)
ECM MAIN RELAY
The ECM main relay is installed in the electric parts holder.
When energized by the turning ignition switch ON, it forms the
circuit which supplies battery voltage to the ECM, injector, igni-
tion coil, IAC valve, CKP sensor and high pressure fuel pump.
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