service engine light is on help

[89crown]

I have a 2003 chrysler 300 M 3.5 automatic and the service engine light came on after an alarm went off and then I notice that my car can't go over 40miles per hour because the transmission was not changing like it suppose to. Can anyone out there maybe tell me what wrong with my car. Thanks

[tinmanwpk]

Originally Posted by 89crown

I have a 2003 chrysler 300 M 3.5 automatic and the service engine light came on after an alarm went off and then I notice that my car can't go over 40miles per hour because the transmission was not changing like it suppose to. Can anyone out there maybe tell me what wrong with my car. Thanks

Either the input or the output speed sensor. A common problem on our transmission. An easy fix if you have any mechanical ability at all. You can change them out yourself for about $50. Does your speedo work? If it does then your input sensor is bad. If it doesn't then your output sensor is bad. One other possibility is a solenoid pack, but it doesn't sound like that. When you change out one sensor you should change the other. If the dealer does it you will be stabbed $$$