Mitsubishi 3000GT Service Manual page 129

MULTIPORT FUEL INJECTION - Troubleshooting
Fault ID
21 Engine Coolant Temperature Sensor
Background
The engine coolant temperature sensor converts the engine
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coolant temperature to a voltage and outputs it.
The engine control module checks whether the voltage is within
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a specified range. In addition, it checks the engine coolant
temperature (signal) does not drop while the engine is warming
Range of Check, Set Conditions
Range of check
Ignition switch : ON
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Excluding 60 seconds after the ignition switch is turned to
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ON or immediately after the engine starts.
Set conditions
Sensor output voltage is 4.6 V or more (corresponding to
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an engine coolant temperature of 45% (-49'F) or less for
4 seconds.
or
Sensor output voltage is 0.1 V or less (correspondinf to an
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engine coolant temperature of 140°C (284'F) or more for
4 seconds.
Range of check
Ignition switch : ON
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Engine spped is approx. 50 r/min or more.
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Set conditions
Ohe sensor output voltage increases from 1.6 V or less
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(corresponding to an engine coolant temperature of 40°C
coolant temperature of 40°C (104°F) or less).
After this, the sensor output voltage is 1.6 V or more for 5
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minutes.
Fault ID
Crankshaft Position Sensor
22
Background
When the engine is running, the crankshaft position sensor
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outputs a pulse signal.
The engine control module checks whether the pulse signal
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is input while the engine is cranking.
The engine control module checks the pulse signal patterns
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of the crankshaft position sensor.
Range of Check, Set Conditions
Range of check
Ignition switch : ON
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Engine is not cranking.
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Set conditions
Regular signal patterns for cylinder discrimination from the
crankshaft position sensor signal and the camshaft position
sensor signal are not input 20 times in a 10 seconds period.
Range of check
Engine is cranking.
Set conditions
Sensor output voltage does not change for 4 seconds (no pulse
signal input).
Title
Limp-in
Controls as if the engine
coolant temperature is
Title
No limp-in
Effect
Engine coolant temperature
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sensor failed.
Open or shorted the engine
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coolant temperature sensor
circuit, or loose connector.
Engine control module failed.
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Effect
Crankshaft position sensor
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failed.
Open or shorted crankshaft
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position sensor circuit, or loose
connector.
Engine control module failed.
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,
Probable causes
Probable causes