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Home >> Lexus >> 2021 >> LS 500 Base, AWD >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Electronically Controlled Brake System (W/ Vacuum Brake Booster) - Diagnostic Codes (2 Of 4) >> ELECTRONICALLY CONTROLLED BRAKE SYSTEM (w/ Vacuum Brake Booster) >> DTC C124A-00: ECM Communication [09/2018 - 10/2023] >> Description

DTC C124A-00: ECM Communication [09/2018 - 10/2023]: Description

The circuit is used to send TRAC and VSC control information from the skid control ECU (brake actuator assembly) to the ECM, and engine control information from the ECM to the skid control ECU (brake actuator assembly) through the CAN communication system.

DTC No. Detection Item DTC Detection Condition Trouble Area Note
C124A-00 ECM Communication Either of the following is detected:
  • The engine type, powertrain variation and destination information sent from the ECM do not match the information stored in the skid control ECU (brake actuator assembly).
  • The vehicle information (DRS availability, VGRS type information and active stabilizer suspension system coordinated control availability information) sent from the VGRS ECU (front steering control ECU) does not match the information stored in the skid control ECU.*
  • The VGRS setting availability information for the steering sensor does not match the information stored in the skid control ECU.
  • No system information stored in the skid control ECU.
  • When the skid control ECU is malfunctioning.
  • Incorrect ECM installed, or ECM malfunction
  • Incorrect VGRS ECU (front steering control ECU) installed, or ECU malfunction*
  • Incorrect steering sensor installed, or sensor malfunction
  • Skid control ECU (Brake actuator assembly)
-
  1. *: w/ Variable Gear Ratio Steering System
C124A-00 DTC DETECTION CONDITIONS

  Vehicle Condition
Pattern 1 Pattern 2* Pattern 3 Pattern 4 Pattern 5
Diagnosis Condition - - - - - -
Malfunction Status The engine type, powertrain variation and destination information sent from the ECM do not match the information stored in the skid control ECU (brake actuator assembly) ◦ - - - -
The vehicle information (DRS availability, VGRS type information and active stabilizer suspension system coordinated control availability information) sent from the VGRS ECU (front steering control ECU) does not match the information stored in the skid control ECU.* - ◦ - - -
The VGRS setting availability information for the steering sensor does not match the information stored in the skid control ECU. - - ◦ - -
No system information stored in the skid control ECU. - - - ◦ -
When the skid control ECU is malfunctioning. - - - - ◦
Detection Time - - - - -
Number of Trips 1 trip 1 trip 1 trip 1 trip 1 trip
  1. *: w/ Variable Gear Ratio Steering System

HINT: 

DTC will be output when conditions for either of the patterns in the table above are met.