DTC U1170-87: Lost Communication with Brake System Control Module (Secondary CAN Line) Missing Message [09/2023 - ]: Description

WARNING: This page is about a different car, the 2024 Lexus TX 500h. However, it is still accessible from the selected car via links, so may be relevant.

The TCM receives signals from the No. 2 skid control ECU (brake actuator assembly) via CAN communication.

If a DTC indicating a CAN communication malfunction is output, repair the CAN communication system prior to diagnosing relevant ECUs or sensors.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	MIL	DTC Output from	Priority	Note
U1170-87	Lost Communication with Brake System Control Module (Secondary CAN Line) Missing Message	No communication between the TCM and No. 2 skid control ECU (brake actuator assembly) for 1 second or more (1-trip detection logic).	CAN communication system No. 2 skid control ECU (brake actuator assembly) TCM	Comes on	Transmission	B	SAE: U1170