Before working on an automatic transmission, our technician must use a transmission diagnosis tool to determine what is wrong.
Many things can cause an automatic transmission to malfunction. The transmission control module (transmission computer) stores error codes that identify or point to the issue.
Sometimes, the control module itself is the issue. When that occurs, the control module may be able to be reprogrammed, or periodically, the module itself must be replaced.Many times, the transmission itself is not the issue.
The transmission control module typically reports: