A problem with a solenoid valve in the transmission may cause the Check Engine (MIL) light to come on.Google+
Car Problem Reports
Chrysler Pacifica Check Engine Light due to problem with solenoid valve
Chrysler Pacifica Problem
Drive Trains Affected: AWD, FWD
Average Mileage: 95,500 mi (73,000 mi - 130,000 mi)
Visitor, 2004 Chrysler Pacifica, AWD, 130,000 mi
Check engine light came on and my transmission would not shift from the gear it was in at that time (2nd) so I hooked it up to my code reader and got a code for my transmission shift solenoid reading fault at the 2/4 circet. After more research on line I found out there was recalls on sertan TCM (transmission control modual) in my year pacifica so I called Chrysler and found it doesn't pertain to my pacifica so I bout a new transmission shift modual I have not put it in yet hope it isn't my t.c.m!!