OBD Guide
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B131B

Left Front Door Ajar Switch Circuit Open

B131B is an OBD-II diagnostic trouble code meaning: Left Front Door Ajar Switch Circuit Open. Common causes: broken wires in the door harness, door sensor malfunction. Estimated repair cost: $11–56.

Severity
✅ Low
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$11–56 (est.)

Symptoms

  • Interior lighting does not work when opening the door
  • Incorrect operation of the central locking
  • False alarms
  • Door open message on dashboard when door is closed

Causes

  • Broken wires in the door harness
  • Door sensor malfunction
  • Oxidation or corrosion of contacts
  • Problems with the sensor connector
  • Damage to wiring during door repair

How to Fix

  1. Check the integrity of the wiring in the door harness
  2. Inspect the contacts of the sensor and connector for oxidation
  3. Replace the door sensor if necessary
  4. Check the operation of the system after repair

Related codes

B131AB131CB131D

FAQ

What does the B131B code mean?

B131B is an OBD-II diagnostic trouble code that indicates: Left Front Door Ajar Switch Circuit Open

What causes a B131B error code?

The most common causes of B131B include: Broken wires in the door harness; Door sensor malfunction; Oxidation or corrosion of contacts; Problems with the sensor connector.

How do I fix a B131B diagnostic trouble code?

To fix B131B: Check the integrity of the wiring in the door harness. Inspect the contacts of the sensor and connector for oxidation. Replace the door sensor if necessary. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B131B?

Limited driving only, diagnose soon

How much does it cost to fix B131B?

The estimated repair cost for B131B is $11–56. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat