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Home >> Lexus >> 2017 >> IS 300 F Sport >> Repair and Diagnosis >> External Pages >> Different car >> Section 4 (Lighting System (Ext) - Diagnostic Codes & Circuit Tests) >> Lighting System >> DTC B243D: Left Low Beam Fan Malfunction; DTC B243E: Right Low Beam Fan Malfunction [09/2020 - ] >> Description

DTC B243D: Left Low Beam Fan Malfunction; DTC B243E: Right Low Beam Fan Malfunction [09/2020 - ]: Description

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The headlight ECU sub-assembly operates the low beam fan to cool the headlight LED unit in order to prevent the headlight LED unit from overheating.

Illuminates the low beam headlights and continuously operates the low beam fan.

The headlight ECU sub-assembly monitors the pulse signals from the FANP terminal when the low beam fans are operating.

HINT: 

If B243D or B243E is output, the headlight ECU sub-assembly performs low beam headlight dimming control.

DTC No. Detection Item DTC Detection Condition Trouble Area DTC Output from
B243D Left Low Beam Fan Malfunction Detection condition: 
  1. All of the following conditions are met:
    • Engine switch on (IG)
    • Low beam headlights on

Malfunction status: 
  1. Fan speed signals from the low beam fan of less than 1600 rpm are continuously detected

Malfunction duration: 
  1. 120 seconds or more
  • Headlight ECU sub-assembly LH
  • Headlight unit assembly LH
 HL AutoLeveling
B243E Right Low Beam Fan Malfunction Detection condition: 
  1. All of the following conditions are met:
    • Engine switch on (IG)
    • Low beam headlights on

Malfunction status: 
  1. Fan speed signals from the low beam fan of less than 1600 rpm are continuously detected

Malfunction duration: 
  1. 120 seconds or more
  • Headlight ECU sub-assembly RH
  • Headlight unit assembly RH
 HL AutoLeveling
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