Grand Caravan AWD V6-3.8L VIN L (2001)
-
Knock sensor
-
Throttle position
-
Exhaust gas oxygen content
-
A/C control positions
-
Battery voltage
-
Vehicle speed
The PCM adjusts injector pulse width and controls injector synchronization by turning the individual ground paths to the injectors ON and OFF.
The PCM adjusts engine idle speed and ignition timing. The PCM adjusts the air/fuel ratio according to the oxygen content in the exhaust gas
(measured by the upstream and downstream heated oxygen sensor).
The PCM monitors for engine misfire. During active misfire and depending on the severity, the PCM either continuously illuminates or flashes the
malfunction indicator lamp (Check Engine light on instrument panel). Also, the PCM stores an engine misfire DTC in memory.
The PCM performs several diagnostic routines. They include:
-
Oxygen sensor monitor
-
Downstream heated oxygen sensor diagnostics during open loop operation (except for shorted)
-
Fuel system monitor
-
EGR monitor
-
Purge system monitor
-
All inputs monitored for proper voltage range.
-
All monitored components (refer to the Emission for On-Board Diagnostics).
The PCM compares the upstream and downstream heated oxygen sensor inputs to measure catalytic convertor efficiency. If the catalyst efficiency
drops below the minimum acceptable percentage, the PCM stores a diagnostic trouble code in memory.
During certain idle conditions, the PCM may enter a variable idle speed strategy. During variable idle speed strategy the PCM adjusts engine
speed based on the following inputs.
-
A/C sense
-
Battery voltage
-
Battery temperature
-
Engine coolant temperature
-
Engine run time
-
Inlet/Intake air temperature
-
Vehicle mileage
Acceleration Mode
This is a CLOSED LOOP mode. The PCM recognizes an abrupt increase in Throttle Position sensor output voltage or MAP sensor output voltage
as a demand for increased engine output and vehicle acceleration. The PCM increases injector pulse width in response to increased fuel demand.
Deceleration Mode
This is a CLOSED LOOP mode. During deceleration the following inputs are received by the PCM:
-
A/C sense
-
Battery voltage
-
Inlet/intake air temperature
-
Engine coolant temperature
-
Crankshaft position (engine speed)
-
Exhaust gas oxygen content (upstream heated oxygen sensor)
-
Knock sensor
-
Manifold absolute pressure
-
Throttle position
-
IAC motor control changes in response to MAP sensor feedback
The PCM may receive a closed throttle input from the Throttle Position Sensor (TPS) when it senses an abrupt decrease in manifold pressure. This
indicates a hard deceleration. In response, the PCM may momentarily turn OFF the injectors. This helps improve fuel economy, emissions and
engine braking.
Wide-Open-Throttle Mode
This is an OPEN LOOP mode. During wide-open-throttle operation, the following inputs are used by the PCM:
-
Inlet/intake air temperature
-
Engine coolant temperature
-
Engine speed
-
Knock sensor
-
Manifold absolute pressure
-
Throttle position