DTC U0101-00: Can Communication: Communication Error To TCM (Can Bus No. 1): Outline

WARNING: This page is about a different car, the 2020 Mazda CX-30. However, it is still accessible from the selected car via links, so may be relevant.

DTC U0101:00 (PCM, SKYACTIV-G) DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location	CAN communication: communication error to TCM (CAN Bus No. 1)
Detection condition	Communication error between the PCM and TCM continues for 5 s or more.
Fail-safe	Controls the turbine rotation signal at 0. Inhibits the AT torque reduction request.
Possible cause	NOTE: During malfunction diagnosis, first verify the malfunction detection of DTC U0074:00 or U0115:00 for the TCM. CAN communication line malfunction between PCM and TCM TCM malfunction PCM malfunction
System wiring diagram	Not applicable
Connector diagram	Not applicable