B1809
Low Severity (Level 2)Lamp Tail Output Circuit Short To Ground
B1809 usually means lamp Tail Output Circuit Short To Ground.
Can you still drive with B1809?
⚠️Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
Typical repair cost: $60 – $700
Severity Level 2 — Low
This code indicates a minor issue that is unlikely to cause immediate driveability problems. You can typically continue driving but should have the vehicle inspected at your earliest convenience.
Common Symptoms
- Body electronics not working or completely dead
- Body electronics blowing fuses when activated
- Zero voltage on the body electrical system circuit — short pulls signal to ground
- Fault may be intermittent — code may clear itself and reappear
- Reduced vehicle functionality related to the body electrical system
Possible Causes
- Chafed or pinched wire in the body electrical system circuit — wire insulation worn through, copper touching vehicle chassis/ground
- Failed body control module (BCM) or sensor with internal short to ground — most common when the component gets wet or overheats
- Corrosion in the electrical connector allowing current to leak to the connector shell/ground
- Damaged wiring harness where it passes through a body panel grommet or near a sharp metal edge
Common Fixes
- Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($31-144 at shop, free at auto parts store for basic scan)
- Visually inspect the body electrical system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $128 diagnostic fee at shop)
- Repair or replace damaged section of wiring harness where short is located — solder and heat-shrink all connections, don't use crimp connectors on critical circuits ($157-333 depending on accessibility)
- If body control module (BCM) or sensor is internally shorted, replace with a quality OEM or OEM-equivalent aftermarket unit ($50-600)
- Clean all ground points related to the body electrical system — remove bolt, sand contact surface to bare metal, apply dielectric grease, and torque to spec ($46-139 at shop)
Estimated Repair Cost
These are estimated costs based on generic repair data. Actual costs may vary depending on your vehicle, location, and labor rates.
Frequently Asked Questions
What does B1809 mean?
B1809 stands for "Lamp Tail Output Circuit Short To Ground". B1809 usually means lamp Tail Output Circuit Short To Ground.
Can you drive with B1809?
Short-distance driving is usually OK, but have this diagnosed within a week to prevent further damage.
How much does it cost to fix B1809?
Repair costs for B1809 typically range from $60 to $700, depending on your vehicle make, model, and local labor rates. Common fixes include: Scan vehicle with a professional-grade OBD2 scanner to read all stored codes and freeze frame data — note the conditions when the code set ($31-144 at shop, free at auto parts store for basic scan); Visually inspect the body electrical system wiring harness and connectors — look for chafed wires, melted insulation, green corrosion, loose pins, or rodent damage (often free to check yourself, $128 diagnostic fee at shop); Repair or replace damaged section of wiring harness where short is located — solder and heat-shrink all connections, don't use crimp connectors on critical circuits ($157-333 depending on accessibility).
Will B1809 clear itself?
Explore Repair Costs
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