The shift solenoids are in the trans (valve body) and the computer tells the trans when to shift through them. Yes this could cause a shift problem. As far as the codes, when a problem occurrs, if it last long enough, the computer will recorde it and save the information in the form of a trouble code. If there is a problem with a shift solenoid, the computer may have saved the info. If the mechanic scans the computer, it may provide a code that will identify the problem and where it is coming from.
Keep in mind, mechanics will usually charge you to scan the computer. However, many nationally recognized parts stores will do it for free.
Let me know if you have other questions.
Wednesday, February 25th, 2009 AT 1:23 PM