LEMON Manuals: Even more car manuals for everyone: 1960-2025
Home >> Dodge and Ram >> 2013 >> Challenger SXT >> Repair and Diagnosis >> Transmission >> Transmission Control Systems >> (Transmission Control Module (TCM) - Electrical Diagnostics) >> DTC Troubleshooting >> U0121-Lost Communication With Anti-Lock Brake Module >> Theory Of Operation
April 5, 2026: LEMON Manuals is launched! Read the announcement.

Theory Of Operation

The Transmission Control Module (TCM) receives information from the Engine, Anti-lock Brake System, and the Electronic Gear Shift control modules over the CAN C bus. The CAN C bus is a high speed communication bus that allows real time control capability between various controllers. Most messages are sent every 20 mSec, this means critical information can be shared between multiple controllers almost instantaneously. The CAN C bus is a two wire bus with a CAN (+) and a CAN (-) circuit. To reduce the potential of radio and other electrical noise interference, the CAN Bus circuit wiring is manufactured using a twisted pair configuration within the electrical wiring harness.