If you get a DTC that you are unsure about, learn more by using our online trouble code library. P0700: Transmission Control System Malfunction.P0613: Transmission Control Module (TCM).Some of the most common TCM trouble codes include: The best way to discern why the Check Engine Light is on is to use your compatible code scanner. You don’t want to assume it has to do with the TCM unless you notice other symptoms from our list. Otherwise, there is a multitude of reasons for the Check Engine Light to come on. If this comes on while there are symptoms of shifting trouble, you know it probably has something to do with the transmission. The first warning sign that something is wrong is when the Check Engine Light comes on the dashboard. There could also be a drop in fuel economy, or the car could go into Limp Mode. The Check Engine Light or Transmission Warning Light could also come on. When the TCM fails, you may notice erratic shifting, that it’s stuck in gear, a slipping transmission or it could stall while shifting. Conclusion Symptoms Of A Bad Transmission Control Module