DTC U1103-87: Lost Communication with Stop and Start Control Module Missing Message [10/2022 - ]: Description

WARNING: This page is about a different car, the 2025 Lexus RX 350, 2024 Lexus RX 350, and 2023 Lexus RX 350. However, it is still accessible from the selected car via links, so may be relevant.

The ECM and engine stop and start ECU send and receive signals via CAN communication.

If a communication error occurs between the ECM and engine stop and start ECU, the ECM stores this DTC.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	DTC Output from	Priority	Note
U1103-87	Lost Communication with Stop and Start Control Module Missing Message	There is no communication between the ECM and engine stop and start ECU (1 trip detection logic).	ECM Engine stop and start ECU CAN Communication System	Does not come on	Engine	B	SAE Code: U1103 DTC for Mexico Models: Applies (Mexico models only)