DTC U0100 Lost Communication with ECM / PCM "A": Description

WARNING: This page is about a different car, the 2008 Toyota Yaris. However, it is still accessible from the selected car via links, so may be relevant.

The combination meter assembly and the ECM exchange signals through the CAN communication system.

DTC TROUBLE DETECTION CONDITION CHART

DTC No.	DTC Detecting Conditions	Trouble Areas
U0100	When either of following conditions detected: Vehicle speed 3.1 mph (5 km/h) or more and IG voltage 10.5 V or more No communication with ECM continues for 3 seconds or more (Communication with neither ECM nor skid control ECU for 60 seconds or more)	CAN communication system ECM