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Home >> Lexus >> 2021 >> RX 350 Base, FWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Cruise Control Systems >> Dynamic Radar Cruise Control System - Diagnostic Codes & Cir Cut Tests >> Dynamic Radar Cruise Control System >> DTC U0100-87: Lost Communication With ECM/PCM "A" Missing Message; DTC U0122-87: Lost Communication with Vehicle Dynamics Control Module Missing Message; DTC U1104-87: Lost Communication with Driving Support ECU Missing Message [09/2015 - 08/2019] >> Description
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DTC U0100-87: Lost Communication With ECM/PCM "A" Missing Message; DTC U0122-87: Lost Communication with Vehicle Dynamics Control Module Missing Message; DTC U1104-87: Lost Communication with Driving Support ECU Missing Message [09/2015 - 08/2019]: Description

The ECM communicates with each sensor and ECU via CAN communication.

If any malfunction is detected in a CAN communication circuit, one or more CAN communication system DTCs are stored.

DTC No. Detection Item DTC Detection Condition Trouble Area MIL
U0100-87 Lost Communication With ECM/PCM "A" Missing Message w/o Full-speed range following function: 
  • While the vehicle speed is 36 km/h (22 mph) or more and the dynamic radar cruise control system is operating, the ECM continuously receives a communication cut-off signal from the skid control ECU (brake actuator assembly) for approximately 1 second or more.

w/ Full-speed range following function: 
  • While the vehicle speed is 5 km/h (3 mph) or more and the dynamic radar cruise control system is operating, the ECM continuously receives a communication cut-off signal from the skid control ECU (brake actuator assembly) for approximately 1 second or more.
  • CAN communication system
  • ECM
  • Skid control ECU (brake actuator assembly)
Does not come on
U0122-87 Lost Communication with Vehicle Dynamics Control Module Missing Message When the engine switch is on (IG) and the dynamic radar cruise control system is operating, a communication error between the skid control ECU (brake actuator assembly) and the ECM is detected for approximately 2.6 seconds or more.
  • CAN communication system
  • ECM
  • Skid control ECU (brake actuator assembly)
Does not come on
U1104-87 Lost Communication with Driving Support ECU Missing Message w/o Full-speed range following function: 
  • While the vehicle speed is 40 km/h (25 mph) or more and the dynamic radar cruise control system is operating, a communication error between the driving support ECU assembly and ECM is detected for 1 second or more.

w/ Full-speed range following function: 
  • While the vehicle speed is 5 km/h (3 mph) or more and the dynamic radar cruise control system is operating, a communication error between the driving support ECU assembly and ECM is detected for 1 second or more.
  • CAN communication system
  • ECM
  • Driving support ECU assembly
Does not come on