RPM downshifting issue on 2001 Chrysler Town & Country

today my engine block light came on and my rpm would not downshift as I accelerated? so at 40 miles an hour my rpms stayed right at 3,000?? please tell me there is a module or part besides the transmission that could need fixing?? Any ideas?
I love this van! please tell me there is an affordable fix!

Asked by for the 2001 Chrysler Town & Country
I see all the major parts manufacturers have a A/T solenoid available usually that means its a common part that fails,Napa Auto Parts has two different solenoids available depending on what transmission you have here are the #s ECH TCS566 ( 4 speed auto ) and ECH TCS559 ( 3 speed auto ) also made by AC Delco, Borg Warner, and Standard Motor Products. Hope this helps.
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Many Chrysler's have what they call a "Limp-in" mode where the computers (control modules) will hold the transmission in 3rd or 4th gear. This allows the customer to be able to make it to a dealer/shop/home while minimizing possible damage to components. With your check engine light on, you'll need to have the computer scanned for trouble codes. There is a service bulletin for a surging problem between 40-50mph but I'm not sure that is the symptom you're describing here.