DTC U0073: Control Module Communication Bus OFF; DTC U0100: Lost Communication With ECM/PCM "A"; DTC U0124: Lost Communication With Lateral Acceleration Sensor Module; DTC U0129: Lost Communication with Brake System Control Module; DTC U0293: Lost Communication With Hybrid Vehicle Control System [04/2018 - 08/2021]: Description

WARNING: This page is about a different car, the 2022 Toyota Avalon, 2021 Toyota Avalon, 2020 Toyota Avalon, and 2019 Toyota Avalon. However, it is still accessible from the selected car via links, so may be relevant.

The parking brake ECU (brake actuator assembly) communicates with the hybrid vehicle control ECU assembly, skid control ECU (brake booster with master cylinder assembly) and deceleration sensor (airbag ECU assembly) via CAN communication.

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Memory	Note
U0073	Control Module Communication Bus OFF	Both of following conditions are met: Power switch on (IG) Bus is off (communication with other ECUs is not possible).	CAN communication system	DTC stored	An electric parking brake system malfunction is displayed on the multi-information display.
U0100	Lost Communication With ECM/PCM "A"	Both of following conditions are met: Vehicle being driven at 6 km/h (4 mph) or more. Parking brake ECU (brake actuator assembly) cannot receive signals from the ECM for approximately 15 seconds.	CAN communication system ECM	DTC stored	An electric parking brake system malfunction is displayed on the multi-information display.
U0124	Lost Communication With Lateral Acceleration Sensor Module	Both of following conditions are met: Vehicle is being driven at 6 km/h (4 mph) or more. Parking brake ECU (brake actuator assembly) cannot receive signals from the deceleration sensor (airbag ECU assembly) for approximately 15 seconds.	CAN communication system Deceleration sensor (Airbag ECU assembly)	DTC stored	An electric parking brake system malfunction is displayed on the multi-information display.
U0129	Lost Communication with Brake System Control Module	Both of following conditions are met: Power switch on (IG). Parking brake ECU (brake actuator assembly) cannot receive signals from the skid control ECU (brake booster with master cylinder assembly) for approximately 15 seconds or 30 seconds (malfunction duration differs depending on the signal).	CAN communication system Skid control ECU (brake booster with master cylinder assembly)	DTC stored	An electric parking brake system malfunction is displayed on the multi-information display.
U0293	Lost Communication With Hybrid Vehicle Control System	Both of following conditions are met: Vehicle being driven at 6 km/h (4 mph) or more. Parking brake ECU cannot receive signals from the hybrid vehicle control ECU for approximately 15 seconds.	CAN communication system Hybrid vehicle control ECU	DTC stored	An electric parking brake system malfunction is displayed on the multi-information display.