RAM 1500 Truck 2WD V8-5.7L VIN 2 (2006)
engine is operating or the starter motor is engaged.
-
The O2S sensor heater element is energized via the ASD or O2S heater relay. The O2S sensor input is not used by the PCM to calibrate air-fuel
ratio during this mode of operation.
ENGINE START-UP MODE
This is an Open Loop mode. The following actions occur when the starter motor is engaged.
The PCM receives inputs from:
-
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
The PCM monitors the crankshaft position sensor. If the PCM does not receive a crankshaft position sensor signal within 3 seconds of cranking the
engine, it will shut down the fuel injection system.
The fuel pump is activated by the PCM through the fuel pump relay.
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 determines the proper ignition timing according to input received from the crankshaft position sensor.
ENGINE WARM-UP MODE
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. Refer to Heating and Air Conditioning.
-
When engine has reached operating temperature, the PCM will begin monitoring O2S 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.
