Voltage Signal: Description and Operation

PURPOSE
Inform the ECM that there is a basic battery voltage problem.

OPERATION
Battery/ignition voltage is an analog input signal read by the ECM. The ignition switched battery voltage circuit is used for this diagnostics.

If voltage is low, the ECM can compensate for a weak spark delivered to the distributor by:
- Increaseing injector on time.
- Increaseing idle RPM.
- Increaseing ignition dwell time.