Slide 74 of 123
Notes:
The EDIS module receives the VRS signal input and converts it to a digital (PIP) signal before passing it along to the PCM. The PCM generates the correct SAW signal and sends it back to the module. The module uses the information in the SAW signal to fire the coils. The module also contains a sequencer responsible for firing the coils in the correct order once the initial firing sequence is determined from the synch signal. The EDIS ignition module contains a sophisticated processor not found in the TFI module
(Compare this strategy to the Reference High and EST circuits seen in the GM section and youÕll see that all of these ignition systems have common features. Knowing the similarities can that can make diagnosis on different systems a lot easier. All of these ignition systems need an engine speed signal, a synch signal to properly sequence coil firing events, and a timing control signal that enables them to produce the best engine performance for actual operating conditions.)
The module also must perform the soft shutdown feature as was previously discussed in the DIS section. Remember, this is the feature that will allow the coils to slowly de-energize if the vehicle is cranked but fails to start. This will prevent a violent kick back sensation from the engine!
