See Figures 1 and 2
The distributorless ignition system, used exclusively for the V10 engine, does not use a conventional mechanical distributor. It is otherwise very similar in function and operation to electronic ignitions found in other Plymouth/Dodge trucks and uses many similar components to the other trucks as well.
The function normally handled by the distributor is given to the Powertrain Control Module (PCM) and an additional Ignition Control Module (ICM). The PCM is a computer containing a microprocessor that sends and receives signals to monitor and regulates engine operation. By controlling the coil ground circuit, the PCM is able to set base timing and adjust the ignition timing advance to meet changing engine operating conditions.
The PCM advances or retards ignition timing based the transmission gear selection and on vital data signals it receives from the following sensors: