RAM 1500 Truck 4WD V8-5.7L VIN D (2005)
This is an Open Loop mode. During engine warm-up, the PCM receives inputs from:
-
Battery voltage
-
Crankshaft position sensor
-
Engine coolant temperature sensor
-
Intake manifold air temperature sensor
-
Manifold absolute pressure (MAP) sensor
-
Throttle position sensor (TPS)
-
Camshaft position sensor signal
-
Park/neutral switch (gear indicator signal-auto. trans. only)
-
Air conditioning select signal (if equipped)
-
Air conditioning request signal (if equipped)
Based on these inputs the following occurs:
-
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 adjusts engine idle speed through the idle air control (IAC) motor and adjusts ignition timing.
-
The PCM operates the A/C compressor clutch through the A/C compressor clutch relay. This is done if A/C has been selected by the vehicle
operator and specified pressures are met at the high and low-pressure A/C switches.
-
When engine has reached operating temperature, the PCM will begin monitoring 02S sensor input. The system will then leave the warm-up mode
and go into closed loop operation.
IDLE MODE
When the engine is at operating temperature, this is a Closed Loop mode. At idle speed, the PCM receives inputs from:
-
Air conditioning select signal (if equipped)
-
Air conditioning request signal (if equipped)
-
Battery voltage
-
Crankshaft position sensor
-
Engine coolant temperature sensor
-
Intake manifold air temperature sensor
-
Manifold absolute pressure (MAP) sensor
-
Throttle position sensor (TPS)
-
Camshaft position sensor signal
-
Battery voltage
-
Park/neutral switch (gear indicator signal-auto. trans. only)
-
Oxygen sensors Based on these inputs, the following occurs:
-
Voltage is applied to the fuel injectors with the ASD relay via the PCM. The PCM will then control injection sequence and injector pulse width by
turning the ground circuit to each individual injector on and off.
-
The PCM monitors the 02S sensor input and adjusts air-fuel ratio by varying injector pulse width. It also adjusts engine idle speed through the idle
air control (IAC) motor.
-
The PCM adjusts ignition timing by increasing and decreasing spark advance.
-
The PCM operates the A/C compressor clutch through the A/C compressor clutch relay. This is done if A/C has been selected by the vehicle
operator and specified pressures are met at the high and low-pressure A/C switches.
CRUISE MODE
When the engine is at operating temperature, this is a Closed Loop mode. At cruising speed, the PCM receives inputs from:
-
Air conditioning select signal (if equipped)
-
Air conditioning request signal (if equipped)
-
Battery voltage
-
Engine coolant temperature sensor
-
Crankshaft position sensor
-
Intake manifold air temperature sensor
-
Manifold absolute pressure (MAP) sensor
-
Throttle position sensor (TPS)
-
Camshaft position sensor signal
-
Park/neutral switch (gear indicator signal-auto. trans. only)
-
Oxygen (02S) sensors Based on these inputs, the following occurs:
-
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.
-
The PCM monitors the 02S sensor input and adjusts air-fuel ratio. It also adjusts engine idle speed through the idle air control (IAC) motor.
-
The PCM adjusts ignition timing by turning the ground path to the coil(s) on and off.
-
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.
