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Home >> Toyota >> 2020 >> Avalon Limited >> Repair and Diagnosis >> External Pages >> Different variant/trim >> Section 31 (Pre-Collision System - Diagnostic Codes (Hybrid)) >> PRE-COLLISION SYSTEM (for HV Model) >> DTC U1104: Lost Communication with Driving Support ECU [04/2018 - 08/2021] >> Description

DTC U1104: Lost Communication with Driving Support ECU [04/2018 - 08/2021]: Description

WARNING: This page is about a different variant/trim than selected.

The driving support ECU assembly is connected to the millimeter wave radar sensor assembly, forward recognition camera and skid control ECU (brake booster with master cylinder assembly) via CAN communication. If communication with the millimeter wave radar sensor assembly, forward recognition camera or skid control ECU (brake booster with master cylinder assembly) stops, the driving support ECU assembly stores DTC U1104.

DTC No. Detection Item DTC Detection Condition Trouble Area
U1104 Lost Communication with Driving Support ECU Any of the following conditions is met:
  • When the power switch is on (IG), a communication error between the driving support ECU assembly and the millimeter wave radar sensor assembly is detected for approximately 0.2 seconds.
  • When the power switch is on (IG), a communication error between the driving support ECU assembly and the forward recognition camera is detected for approximately 0.3 seconds.
  • When the power switch is on (IG), a communication error between the driving support ECU assembly and the skid control ECU (brake booster with master cylinder assembly) is detected for approximately 1.5 seconds.
  • CAN communication system
  • CAN bus line
  • Front camera system
  • Electronically controlled brake system
  • Millimeter wave radar sensor assembly
  • Forward recognition camera
  • Driving support ECU assembly
DTC DETECTION CONDITIONS:

  Vehicle Condition
Pattern 1 Pattern 2 Pattern 3
Diagnosis Condition Power switch is on (IG)
Malfunction Status A communication error between the driving support ECU assembly and the millimeter wave radar sensor assembly is detected - -
A communication error between the driving support ECU assembly and the forward recognition camera is detected - -
A communication error between the driving support ECU assembly and the skid control ECU (brake booster with master cylinder assembly) is detected - -
Detection Time Approximately 0.2 seconds or more Approximately 0.3 seconds or more Approximately 1.5 seconds or more
Number of Trips 1 trip 1 trip 1 trip

HINT: 

DTC will be stored when conditions of any pattern in the table above are met.