Caravan FWD V6-201 3.3L VIN R MFI (1997)
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Torque Converter Clutch Solenoid (3 speed transmission)
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Transmission Control Module
Based on inputs it receives, the PCM adjusts fuel injector pulse width, idle speed, ignition spark advance, ignition coil dwell and canister purge
operation. The PCM regulates the cooling fan, air conditioning and speed control systems. The PCM changes generator charge rate by adjusting
the generator field.
The PCM adjusts injector pulse width (air/fuel ratio) based on the following inputs:
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Battery voltage
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Engine coolant temperature
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Exhaust gas content (oxygen sensors)
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Engine speed (crankshaft position sensor)
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Manifold absolute pressure
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Throttle position
The PCM adjusts ignition timing based on the following inputs:
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Barometric pressure
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Engine coolant temperature
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Engine speed (crankshaft position sensor)
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Manifold absolute pressure
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Throttle position
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Transaxle gear selection (park/neutral switch)
The PCM also adjusts engine idle speed through the idle air control motor based on the following inputs:
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Air conditioning select switch head pressure
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Brake switch
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Engine coolant temperature
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Engine speed (crankshaft position sensor)
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Manifold absolute pressure
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Throttle position
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Transaxle gear selection (park/neutral switch)
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Vehicle distance (speed)
Automatic Shutdown (ASD) and Fuel Pump Relays
The Automatic Shutdown (ASD) and fuel pump relays are located in the Power Distribution Center (PDC).
The camshaft position sensor and crankshaft position sensor signals are sent to the PCM.
If the PCM does not receive both signals within approximately one second of engine cranking, it deactivates the ASD relay and fuel pump relay.
When these relays are deactivated, power is shut off to the fuel injectors, ignition coil, oxygen sensor heating element and fuel pump.
PCM Regulated Output Voltages
The PCM contains a voltage converter that changes battery voltage to a regulated 8.0 volts to power the camshaft position sensor, crankshaft
position sensor and vehicle speed sensor. The PCM also provides a 5.0 volt supply for the manifold absolute pressure sensor, throttle position
sensor and engine coolant temperature sensor.
CIRCUIT OPERATION
Battery Feed
Circuit A14 from fuse 13 in the Power Distribution Center (PDC) supplies battery voltage to cavity 46 of the Powertrain Control Module (PCM).
Helpful Information
Circuit A14 connects to a bus bar in the PDC that the battery feeds. Circuit A14 powers the Automatic Shut Down (ASD) relay and fuel pump
relay. The A14 circuit also splices to the data link connector.
Power (Device) Ground
Circuit Z12 attaches to cavity 10 of the PCM and circuit Z11 connects to cavity 50 of the PCM. The Z11 and Z12 circuits provide ground for
PCM internal drivers that operate high current devices like the injectors and ignition coils.
Helpful Information
If the system loses ground for circuits Z11 and Z12, the vehicle will not operate.
