RAM 2500 Truck 4WD L6-5.9L DSL Turbo VIN 7 (2001)
When the engine is at operating temperature, this is a Closed Loop mode. At cruising speed, the PCM receives inputs from:
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Air conditioning select signal (if equipped)
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Air conditioning request signal (if equipped)
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Battery voltage
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Engine coolant temperature sensor
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Crankshaft position 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)
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Park/neutral switch (gear indicator signal-auto. trans. only)
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Oxygen (O2S) sensors
Based on these inputs, 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 adjust the injector pulse width by turning the
ground circuit to each individual injector ON and OFF.
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The PCM monitors the O2S sensor input and adjusts air-fuel ratio. It also adjusts engine idle speed through the idle air control (IAC) motor.
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The PCM adjusts ignition timing by turning the ground path to the coil ON and OFF.
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The PCM operates the A/C compressor clutch through the clutch relay. This happens if A/C has been selected by the vehicle operator and
requested by the A/C thermostat.
Acceleration Mode
This is an Open Loop mode. The PCM recognizes an abrupt increase in throttle position or MAP pressure as a demand for increased engine output
and vehicle acceleration. The PCM increases injector pulse width in response to increased throttle opening.
Deceleration Mode
When the engine is at operating temperature, this is an Open Loop mode. During hard deceleration, the PCM receives the following inputs.
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Air conditioning select signal (if equipped)
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Air conditioning request signal (if equipped)
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Battery voltage
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Engine coolant temperature sensor
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Crankshaft position sensor
-
Intake manifold air temperature sensor
-
Manifold absolute pressure (MAP) sensor
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Throttle position sensor (TPS)
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Camshaft position sensor signal (in the distributor)
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Park/neutral switch (gear indicator signal-auto. trans. only)
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Vehicle speed sensor
If the vehicle is under hard deceleration with the proper rpm and closed throttle conditions, the PCM will ignore the oxygen sensor input signal.
The PCM will enter a fuel cut-off strategy in which it will not supply a ground to the injectors. If a hard deceleration does not exist, the PCM will
determine the proper injector pulse width and continue injection.
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
-
Throttle position sensor (TPS)
-
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.
