ENGINE CONTROL SYSTEM 3-29
CONDITION FOR SELF-DIAGNOSTIC SYSTEM OPERATION
NOTE 1:
These conditions will be caused by IAC valve failure or incor-
rect 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.
NOTE 2:
This condition will be caused by clogged pressure detect pas-
sage in intake manifold.
FAILED ITEM CONDITION
MAP sensor 1
CKP sensor
CMP sensor
CTP switch
Cylinder temp. sensor
IAT sensor
MAP sensor 2
(Pressure detect passage)
Rectifier & regulator
(Over-charging )
Exhaust manifold temp. sensor
IAC valve / By-pass air screw
adjustment
• During one crankshaft rotation, 34 signals are not input to the ECM
• No signal (With engine running)
• Receiving an out of range “37–860 mmHg (0.20–4.53V)” signal
(With engine running)
• IAC valve operates at 90% duty or higher when CTP switch is “ON”
[NOTE 1]
• During two crankshaft rotations, 4 signals are not input to the ECM
• Receiving “ON” signal when engine speed is 2500 r/min. or higher and intake
manifold pressure is 319 mmHg or higher
• No signal
• Receiving an out of range “– 46 to +170 °C (0.10 – 4.63V)” signal
• No signal
• Receiving an out of range “– 46 to +178 °C ( 0.04 – 4.46V)” signal
• Receiving unchanging signal regardless engine speed change
[NOTE 2]
• Receiving 16 volts or higher signal
• No signal
• Receiving an out of range “– 46 to +170 °C (0.10 – 4.63V)” signal
Fuel injector • No operation signal from the ECM
PassagePassage
CMP sensorCMP sensor
O-ringO-ring