DTC U0401-68; Error Signal Received From Pcm: Notes

WARNING: This page is about a different car, the 2017 Mazda 3. However, it is still accessible from the selected car via links, so may be relevant.

DETECTION CONDITION & POSSIBLE CAUSE

Description	Error signal received from PCM
Detection condition	Front body control module (FBCM) receives the error ECT sensor or ambient temperature sensor signals from the PCM for 5 s or more with the ignition switched ON (engine off or on).
Fail-safe function	Not applicable
Possible cause	ECT sensor malfunction Ambient temperature sensor malfunction PCM malfunction Front body control module (FBCM) malfunction
System wiring diagram	Not applicable