DTC U0100: Lost Communication with ECM / PCM "A" [09/2014 - 11/2017]: Description

WARNING: This page is about a different car, the 2017 Lexus RC 350, 2016 Lexus RC 350, and 2015 Lexus RC 350. However, it is still accessible from the selected car via links, so may be relevant.

The ECM communicates with the TCM via the Controller Area Network (CAN).

If there is a problem in communication, the TCM stores this DTC.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	Memory
U0100	Lost Communication with ECM / PCM "A"	1. Diagnosis Condition 2. Malfunction Status 3. Malfunction Time 4. Other The engine switch is on (IG) and battery voltage is 10.5 V or more. There is no communication between the ECM and TCM. 1.25 seconds or more 1-trip detection logic	Harness and connector ECM TCM	Comes on	DTC stored