DTC U0140-00: Communication Error With Body Control Module (BCM) [Connectivity Master Unit]: 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 U0140:00 (CONNECTIVITY MASTER UNIT) DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location	Communication error with body control module (BCM)
Detection condition	The connectivity master unit (CMU) detects a communication interruption or communication error with the body control module (BCM) for approx. 6 s.
Fail-safe	The connectivity master unit (CMU) is put in sleep mode and it does not launch.
Possible cause	Malfunction in CAN bus communication line Connectivity master unit (CMU) malfunction Body control module (BCM) malfunction
System wiring diagram	Not applicable