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Home >> Lexus >> 2020 >> LS 500h AWD >> Repair and Diagnosis (Single Page) >> Accessories & Equipment >> Exterior Lights >> Lighting System (Ext) - Diagnostic Codes (1 Of 2) >> Lighting System >> DTC B242E: Open in IG Circuit [10/2017 - 10/2022] >> Description

DTC B242E: Open in IG Circuit [10/2017 - 10/2022]: Description

The headlight ECU sub-assembly operates using the power source voltage input from the IG terminal and ECUB terminal.

The IG terminal power source voltage is supplied by turning the IG1 relay to ON.

The headlight ECU sub-assembly receives power switch on (IG) signals from the main body ECU (multiplex network body ECU) via CAN communication, compares the power switch on (IG) signal and the power source voltage supply condition of the IG terminal and monitors the result.

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from Note
B242E Open in IG Circuit Detection condition: 
  1. Power switch on (IG)

Malfunction status: 

  1. When the IG terminal power source voltage is 0 V (power switch off), IG ON signals from the main body ECU (multiplex network body ECU) via CAN communication are continuously received

Malfunction duration: 

  1. 10 seconds or more
  • Headlight ECU sub-assembly LH
  • Harness or connector
AFS -
DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from Note
B242E Open in IG Circuit Detection condition: 
  1. Power switch on (IG)

Malfunction status: 

  1. When the IG terminal power source voltage is 0 V (power switch off), IG ON signals from the main body ECU (multiplex network body ECU) via CAN communication are continuously received

Malfunction duration: 

  1. 10 seconds or more
  • Headlight ECU sub-assembly RH
  • Harness or connector
AFS (Sub) -