RAM 2500 Truck 2WD L6-5.9L DSL Turbo VIN C (2002)
Based on the above inputs, the PCM will adjust engine idle speed through the idle air control (IAC) motor.
The PCM adjusts ignition timing by turning the ground path to the coil ON and OFF.
Wide Open Throttle Mode
This is an Open Loop mode. During wide open throttle operation, the PCM receives the following inputs.
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Battery voltage
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Crankshaft position sensor
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Engine coolant temperature sensor
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Intake manifold air temperature sensor
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Manifold absolute pressure (MAP) sensor
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Throttle position sensor (TPS)
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Camshaft position sensor signal (in the distributor)
During wide open throttle conditions, the following occurs:
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Voltage is applied to the fuel injectors with the ASD relay via the PCM. The PCM will then control the injection sequence and injector pulse width
by turning the ground circuit to each individual injector ON and OFF. The PCM ignores the oxygen sensor input signal and provides a
predetermined amount of additional fuel. This is done by adjusting injector pulse width.
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The PCM adjusts ignition timing by turning the ground path to the coil ON and OFF.
Ignition Switch Off Mode
When ignition switch is turned to OFF position, the PCM stops operating the injectors, ignition coil, ASD relay and fuel pump relay.
5 VOLT SUPPLIES
Two different Powertrain Control Module (PCM) 5 volt supply circuits are used; Primary and Secondary.
Primary 5-Volt Supply
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supplies the required 5 volt power source to the Crankshaft Position (CKP) sensor.
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supplies the required 5 volt power source to the Camshaft Position (CMP) sensor.
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supplies a reference voltage for the Manifold Absolute Pressure (MAP) sensor.
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supplies a reference voltage for the Throttle Position Sensor (TPS) sensor.
Secondary 5-Volt Supply
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supplies the required 5 volt power source to the oil pressure sensor.
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supplies the required 5 volt power source for the Vehicle Speed Sensor (VSS) (if equipped).
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supplies the 5 volt power source to the transmission pressure sensor (if equipped with an RE automatic transmission).
IGNITION CIRCUIT SENSE
This circuit ties the ignition switch to the Power- train Control Module (PCM).
The ignition circuit sense input tells the PCM the ignition switch has energized the ignition circuit.
Battery voltage is also supplied to the PCM through the ignition switch when the ignition is in the RUN or START position. This is referred to as the
ignition sense circuit and is used to wake up the PCM. Voltage on the ignition input can be as low as 6 volts and the PCM will still function. Voltage is
supplied to this circuit to power the PCM's 8-volt regulator and to allow the PCM to perform fuel, ignition and emissions control functions.
POWER GROUNDS
The Powertrain Control Module (PCM) has 2 main grounds. Both of these grounds are referred to as power grounds. All of the high-current, noisy,
electrical devices are connected to these grounds as well as all of the sensor returns. The sensor return comes into the sensor return circuit, passes
through noise suppression, and is then connected to the power ground.
The power ground is used to control ground circuits for the following PCM loads:
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Generator field winding
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Fuel injectors
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Ignition coil(s)
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Certain relays/solenoids
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Certain sensors
SENSOR RETURN
