Powertrain Control Module - Component Information - Diagrams - Page 2081
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High Speed Fan Relay
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Idle Air Control Motor
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Ignition Coils
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Leak Detection Pump
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Low Speed Fan Relay
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MTV Actuator
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Proportional Purge Solenoid
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SRV Valve
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Speed Control Relay
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Speed Control Vent Relay
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Speed Control Vacuum Relay
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8 Volt Output
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5 Volt Output
Based on inputs it receives, the powertrain control module (PCM) adjusts fuel injector pulse width, idle speed, ignition timing, and canister purge
operation and EGR if equipped. The PCM regulates the cooling fans, 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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Manifold Absolute Pressure
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Engine Speed (crankshaft position sensor)
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Battery Voltage
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Intake Air Temperature Sensor
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Engine Coolant Temperature
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Exhaust Gas Oxygen Content (heated oxygen sensors)
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Throttle Position
The PCM adjusts engine idle speed through the idle air control motor based on the following inputs.
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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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Park/Neutral (transmission gear selection)
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Transaxle Gear Engagement
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Throttle Position
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Vehicle Speed (from Transmission Control Module)
The PCM adjusts ignition timing based on the following inputs.
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Intake Air Temperature
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Engine Coolant Temperature
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Engine Speed (crankshaft position sensor)
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Knock Sensor
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Manifold Absolute Pressure
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Park/Neutral (transmission gear selection)
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Transaxle Gear Engagement
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Throttle Position
The automatic shut down (ASD) and fuel pump relays are mounted externally but turned ON and OFF by the powertrain control module through
the same circuit.
The camshaft and crankshaft signals are sent to the powertrain control module. If the PCM does not receive both signals within approximately one
second of engine cranking, it deactivates the ASD and fuel pump relays. When these relays are deactivated, power is shut off to the fuel injectors,
ignition coils, fuel pump and the heating element in each oxygen sensor.
The PCM contains a voltage converter that changes battery voltage to a regulated 8.0 volts. The 8.0 volts power the camshaft position sensor,
crankshaft position sensor and vehicle speed sensor. The PCM also provides a 5.0 volts supply for the engine coolant temperature sensor, intake
air temperature sensor, manifold absolute pressure sensor and throttle position sensor EGR (if equipped).
The PCM engine control strategy prevents reduced idle speeds until after the engine operates for 320 km (200 miles). If the PCM is replaced after
320 km (200 miles) of usage, update the mileage in new PCM. Use the DRB scan tool to change the mileage in the PCM. Refer to the appropriate
Powertrain Diagnostic Manual and the DRB scan tool. If equipped with SKIM, must use SKIM function to reprogram VIN number in new PCM.
SENSOR RETURN - PCM INPUT
The sensor return circuit provides a low electrical noise ground reference for all of the systems sensors. The sensor return circuit connects to
internal ground circuits within the Powertrain Control Module (PCM).
SCI RECEIVE - PCM INPUT