Grand Caravan V6-3.8L VIN L (2007)
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Manifold Absolute Pressure
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Park/Neutral
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Transaxle Gear Engagement
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Throttle Position
The automatic shut down (ASD) and fuel pump relays are mounted externally, but turned on and off by the powertrain control module through the same
circuit.
The camshaft and crankshaft signals are sent to the powertrain control module. If the PCM does not receive both signals within approximately one
second of engine cranking, it deactivates the ASD and fuel pump relays. When these relays are deactivated, power is shut off to the fuel injectors,
ignition coils, fuel pump and the heating element in each oxygen sensor.
The PCM contains a voltage converter that changes battery voltage to a regulated 8.0 volts. The 8.0 volts power the camshaft position sensor, crankshaft
position sensor and vehicle speed sensor. The PCM also provides a 5.0 volts supply for the engine coolant temperature sensor, intake air temperature
sensor, manifold absolute pressure sensor and throttle position sensor.
The PCM engine control strategy prevents reduced idle speeds until after the engine operates for 320 km (200 miles). If the PCM is replaced after 320
km (200 miles) of usage, update the mileage in new PCM. Use the DRBIII(R) scan tool to change the mileage in the PCM.
TRANSMISSION CONTROL
CLUTCH VOLUME INDEX (CVI)
An important function of the PCM is to monitor Clutch Volume Index (CVI). CVIs represent the volume of fluid needed to compress a clutch pack.
The PCM monitors gear ratio changes by monitoring the Input and Output Speed Sensors. The Input, or Turbine Speed Sensor sends an electrical signal
to the PCM that represents input shaft rpm. The Output Speed Sensor provides the PCM with output shaft speed information.
By comparing the two inputs, the PCM can determine transaxle gear ratio. This is important to the CVI calculation because the PCM determines CVIs by
monitoring how long it takes for a gear change to occur (Figure 2).
Figure 2 Example of CVI Calculation
