Oldsmobile/Buick Repair: transmission problem with 1995 Saturn SL1, vehicle speed sensor, saturn sl1

Question
low mileagg saturn 1995 SL1  works and shifts fine when cold and short trips but when hot (15+ miles and then in stop and go)wil not shift into third and fourth gear and stays in first and second. when the car sits and cools down it shifts properly thru all four gears properly . also engine svc lite comes on just before this happens  so i connected a code reader and the code23-mat sensor or tps fault and code 24-vehicle speed sensor or circuit fault both showed. so my question is how do i further diagnose or repair this problem ? obviously your guidance will be appreciated   thanks art

Answer
You need to FIX the faults that are causing the codes. It is most likely that the code 24 is probably causing your shifting problems since the shift timing is controlled by the VSS sensor input.


Your going to need a service manual in order to diagnose the codes. Do NOT purchase a GENERIC book such as Chiltons, Hayes, etc as they LACK the SPECIFIC information and testing procedures that you MUST have which you can ONLY get from the manufacturers service manuals that you can purchase online thru HELMS books.


autohelp