TCIL Always On When Engine Is Running, No DTCs Are Present

Check TCIL circuits. On Continental, Focus, LS, Mustang, Thunderbird, Town Car or Windstar, see appropriate INSTRUMENT PANELS article in ACCESSORIES & EQUIPMENT. On all other models, go to TEST TB, step 6)  under SYSTEM TESTS in SELF-DIAGNOSTICS - EEC-V - GASOLINE & NGV article.