Download The TCM is reporting internal errors. Diagnostic Procedure 1. Turn ignition switch to LOCK position. Remove transmission control relay. Measure resistance between ground and relay ground circuit (Black/Yellow wire) in relay connector. If resistance is greater than 5 ohms, repair open circuit. If resistance s not greater than 5 ohms, go to next step. 2. The TCM has an internal problem and must be replaced. P0715: INPUT SPEED SENSOR ERROR Circuit Description DTC P0715 will set if an excessive change in input RPM has been detected in any gear. Possible Causes Intermittent wiring and connector problems. Faulty input speed sensor. Input speed sensor circuits shorted to ground, shorted to voltage, or open. Faulty TCM.