ENGINE CONTROL SYSTEM 3-28
CONDITION FOR SELF-DIAGNOSTIC SYSTEM OPERATION
[NOTE 1]
These conditions will be caused by IAC valve failure or incorrect by-pass air screw adjustment. If IAC valve
is always closed or by-pass air is too low, the ECM controls the IAC valve duty to increase to maintain the
idling/trolling speed specified.
Conversely, if IAC valve is always opened or by -pass air is too high, the ECM controls the IAC valve duty to
decrease to maintain the idling / trolling speed specified.
[NOTE 2]
This condition will be caused by disconnected, kinked or clogged MAP sensor hose or clogged inlet mani-
fold gas filter.
MAP sensor 1 • No signal (With engine running)
• Receiving an out of range “37 – 860 mmHg (0.50 – 4.84V)”
signal ( With engine running )
CKP sensor • No signal from any CKP sensors while receiving 8 signals from other
CKP sensors.
• No signal from one CKP sensor while receiving 6 signals from CMP
sensor. (One CKP sensor fail)
IAC valve / By-pass air screw • IAC valve operates at 90% duty or higher when CTP switch is “ON”
adjustment • IAC valve operates at 10% duty or lower when CTP switch is “ON”
[NOTE 1]
CMP sensor • No signal while receiving 12 signals from CKP sensors
CTP switch • Receiving “ON” signal when engine speed is 2500 r/ min or higher and
intake manifold pressure is 380 mmHg or higher.
Cylinder temp. sensor • No signal
• Receiving an out of range “– 46 to +170 °C (0.10 – 4.84 V)” signal
IAT sensor • No signal
• Receiving an out of range “– 46 to +169 °C ( 0.10 – 4.88V)” signal
MAP sensor 2 • Receiving unchanging signal regardless engine speed change
(Sensor hose) [NOTE 2]
Rectifier & regulator • Receiving 16 volts or higher signal
(Over-charging )
Exhaust manifold temp, sensor • No signal
• Receiving an out of range “– 46 to +170 °C (0.10 – 4.84V)” signal
FAILED ITEM CONDITION
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