Posts Tagged: lost communication with TCM Toyota

Toyota U0101 Code: Causes, Symptoms, and Proven Fixes

What Causes a Toyota U0101 Code and How to Fix It Quick Summary The U0101 code indicates a loss of communication with the transmission control module (TCM). When I see this code, I immediately think “network problem,” not a bad transmission or bad transmission control module.  The most common causes I’ve seen are: • Wiring faults, • Low system voltage • A failed skid control (ABS) module that knocks out the network. The fix is never guesswork. You confirm power, ground, and CAN communication before replacing anything. What a Toyota … Read More