Vision V6-201 3.3L (1993)
Powertrain Control Module: Description and Operation
Modes of Operation
Acceleration (Except Wide Open Throttle)
This is a CLOSED LOOP mode.
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The PCM recognizes an abrupt increase in throttle position or MAP pressure, as a demand for increased engine output to accelerate vehicle.
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The PCM increases injector pulse width, in response to increased fuel demand.
Deceleration
This is a CLOSED LOOP mode.
During deceleration the the PCM receives inputs from:
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Air Conditioning Control Position
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Battery voltage
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Camshaft position (CMP) sensor
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Engine coolant temperature (ECT) sensor
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Manifold Absolute Pressure (MAP) sensor
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Intake air temperature (IAT) sensor (3.5L)
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Crankshaft position (CKP) sensor
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Throttle Position Sensor (TPS)
Based on these inputs the PCM will:
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Determine, based on O2 sensor input, proper injector pulse width and continue injection.
Idle/Cruise
This is a CLOSED LOOP mode.
With engine at idle or cruise, at operating temperature, the PCM receives inputs from:
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Air Conditioning Control Position
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Battery voltage
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Camshaft position (CMP) sensor
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Engine coolant temperature (ECT) sensor
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Manifold absolute pressure (MAP) sensor
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Intake air temperature (IAT) sensor
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Crankshaft position (CKP) sensor
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Throttle position sensor (TPS)
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Heated oxygen sensor (O2S)
Based on these inputs the PCM will:
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Apply voltage to the injectors. The PCM then controls injection sequence and pulse width by switching individual injector ground paths on and
off.
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Monitor oxygen sensor and fine tune air/fuel ratio by varying injector pulse width.
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Adjust engine idle speed through the IAC motor.
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Adjust ignition timing.