DTC U2121-00: Can Communication - Communication Error To Vehicle Control Module (VCM): Outline

DTC U2121:00 (PCM, SKYACTIV-G, US) DETECTION CONDITION AND POSSIBLE CAUSE

System malfunction location	CAN communication: communication error to vehicle control module (VCM)
Detection condition	Communication error between the PCM and vehicle control module (VCM) continues for 5 s or more.
Fail-safe	Inhibits engine-stop by operating the i-stop function. (With i-stop system)
Possible cause	CAN communication line malfunction between PCM and vehicle control module (VCM) Vehicle control module (VCM) malfunction (built-into body control module (BCM)) PCM malfunction
System wiring diagram	Not applicable
Connector diagram	Not applicable