Ignition Signal
WARNING: This page is about a different car, the 2002 Dodge Intrepid, 2002 Chrysler Intrepid, 2002 Chrysler Concorde, and 2002 Chrysler 300M. However, it is still accessible from the selected car via links, so may be relevant.
When ignition is turned to OFF, ON or START position, PCM checks the incoming voltage. If voltage is less than specified or exceeds specified voltage, PCM will cause transaxle to enter limp-in mode to prevent damage to electrical components.
When ignition is turned on, PCM performs a series of circuit and relay checks. If no problem is present, PCM provides voltage to transmission control relay, causing contacts to close which supplies voltage to solenoid assembly and PCM. Voltage supplied to PCM is referred to as switched battery voltage. If a problem is present, PCM turns off power supply to transmission control relay, which causes transaxle to enter limp-in mode.