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Home >> Lexus >> 2020 >> LS 500 Base, AWD >> Repair and Diagnosis (Single Page) >> Steering >> Manual Steering >> Variable Gear Ratio Steering System - Diagnostic Codes & Symptom Tests >> Variable Gear Ratio Steering System >> DTC U0100: Lost Communication with ECM / PCM "A"; DTC U0101: Lost Communication with TCM; DTC U0125: Lost Communication with Yaw Rate Sensor Module; DTC U0126: Lost Communication with Steering Angle Sensor Module; DTC U0129: Lost Communication with Brake System Control Module; DTC U0131: Lost Communication with Power Steering Control Module; DTC U0134: Lost Communication with DRS Module [12/2017 - 10/2023] >> Description
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DTC U0100: Lost Communication with ECM / PCM "A"; DTC U0101: Lost Communication with TCM; DTC U0125: Lost Communication with Yaw Rate Sensor Module; DTC U0126: Lost Communication with Steering Angle Sensor Module; DTC U0129: Lost Communication with Brake System Control Module; DTC U0131: Lost Communication with Power Steering Control Module; DTC U0134: Lost Communication with DRS Module [12/2017 - 10/2023]: Description

The VGRS ECU (front steering control ECU) receives signals from the ECM, skid control ECU (brake actuator assembly)*1, skid control ECU assembly*2, yaw rate sensor, steering sensor, rack and pinion power steering gear assembly and DRS ECU (rear steering control ECU) via CAN communication. When DTCs indicating a CAN communication system malfunction are output, repair the CAN communication system first.

  1. *1: w/ Vacuum Brake Booster
  2. *2: w/o Vacuum Brake Booster
DTC No. Detection Item DTC Detection Condition Trouble Area Warning Indicate Return-to-normal Condition
U0100 Lost Communication with ECM / PCM "A" All conditions are met:
  • 1 second or more elapse after turning the engine switch on (IG).
  • Before control starts.
  • Power source voltage at 10 to 16 V.
  • The signal from the ECM is lost for approximately 3 seconds or more.
  • ECM
  • CAN communication system
 Comes on
  • The system recovers from the communication stop
  • Turn the engine switch on (IG) again
U0101 Lost Communication with TCM All conditions are met:
  • 1 second or more elapse after turning the engine switch on (IG).
  • Power source voltage at 10 to 16 V.
  • The signal from the ECM is lost for approximately 12 seconds or more.
  • ECM
  • CAN communication system
 Comes on
  • The system recovers from the communication stop
  • Turn the engine switch on (IG) again
U0125 Lost Communication with Yaw Rate Sensor Module All conditions are met:
  • 1 second or more elapse after turning the engine switch on (IG).
  • Power source voltage at 10 to 16 V.
  • The signal from the yaw rate sensor is lost for approximately 12 seconds or more.
  • Yaw rate sensor
  • CAN communication system
 Comes on
  • The system recovers from the communication stop
  • Turn the engine switch on (IG) again
U0126 Lost Communication with Steering Angle Sensor Module All conditions are met:
  • 1 second or more elapse after turning the engine switch on (IG).
  • Power source voltage at 10 to 16 V.
  • The signal from the steering sensor is lost for approximately 3 seconds or more.
  • Steering sensor
  • CAN communication system
 Comes on
  • The system recovers from the communication stop
  • Turn the engine switch on (IG) again
U0129 Lost Communication with Brake System Control Module All conditions are met:
  • 2 seconds or more elapse after turning the engine switch on (IG).
  • Power source voltage at 10 to 16 V.
  • The signal from the skid control ECU (brake actuator assembly)*1 or skid control ECU assembly*2 is lost for approximately 3 seconds or more.
  • Skid control ECU (brake actuator assembly)*1
  • Skid control ECU assembly*2
  • CAN communication system
 Comes on
  • The system recovers from the communication stop
  • Turn the engine switch on (IG) again
U0131 Lost Communication with Power Steering Control Module All conditions are met:
  • 1 second or more elapse after turning the engine switch on (IG).
  • Power source voltage at 10 to 16 V.
  • The signal from the rack and pinion power steering gear assembly is lost for approximately 3 seconds or more.
  • Rack and pinion power steering gear assembly
  • CAN communication system
 Comes on
  • The system recovers from the communication stop
  • Turn the engine switch on (IG) again
U0134 Lost Communication with DRS Module All conditions are met:
  • 1 second or more elapse after turning the engine switch on (IG).
  • Power source voltage at 10 to 16 V.
  • The signal from the DRS ECU (rear steering control ECU) is lost for approximately 3 seconds or more.
  • DRS ECU (rear steering control ECU)
  • CAN communication system
 Comes on
  • The system recovers from the communication stop
  • Turn the engine switch on (IG) again
  1. *1: w/ Vacuum Brake Booster
  2. *2: w/o Vacuum Brake Booster
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