OBD-II FAULT CODE
B1809

Lamp Tail Output Circuit Short To Ground

Reference information for B1809. Because this is manufacturer-specific, confirm the exact definition for the vehicle before using the diagnostic guidance below.

Manufacturer-specific code

This code can have different meanings depending on vehicle make, model and year. Treat the definition below as a reference and confirm it with OEM service information before diagnosis or repair.

BodySystem
LightingCategory
MediumSeverity
  • Body/accessory warning lamp or feature not working
  • Blown bulb/LED module
  • Poor ground
  • Fuse/relay fault
  • Switch/module/wiring issue
  • Wire shorted to chassis/ground
  • Check related fuses, connectors, grounds and switch/module power supply
  • Check bulb/module, fuse, ground and connector corrosion
  • Inspect harness for rubbing/pinch points and check resistance to ground
  • Replace failed bulb/module, repair ground/wiring, replace switch/relay if confirmed
  • Repair insulation/harness damage or replace internally shorted component
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Disclaimer: Information is provided for general guidance only and may not apply to all vehicles. Always consult a qualified technician.