OBD Guide

B3685

Movable Roof Header Latched Left Sensor Circuit

B3685 is an OBD-II diagnostic trouble code meaning: Movable Roof Header Latched Left Sensor Circuit. Common causes: open or short circuit in wiring harness, oxidized or damaged sensor contacts. Estimated repair cost: $56–167.

Severity
⚠️ Medium
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–167 (est.)

Symptoms

  • The airbag malfunction indicator comes on
  • Security error message on display
  • The curtain airbag may not deploy in an accident.

Causes

  • Open or short circuit in wiring harness
  • Oxidized or damaged sensor contacts
  • Faulty curtain fixation sensor
  • Problems with the SRS control unit

How to Fix

  1. Run diagnostics on the SRS system to confirm the error.
  2. Visually inspect the wiring harness and sensor contacts
  3. Check the sensor resistance according to the manual
  4. Replace the sensor or restore circuit integrity if necessary
  5. Clear the error and check if it comes back

Related codes

Error B3685 by Vehicle Brand

FAQ

What does the B3685 code mean?

B3685 is an OBD-II diagnostic trouble code that indicates: Movable Roof Header Latched Left Sensor Circuit

What causes a B3685 error code?

The most common causes of B3685 include: Open or short circuit in wiring harness; Oxidized or damaged sensor contacts; Faulty curtain fixation sensor; Problems with the SRS control unit.

How do I fix a B3685 diagnostic trouble code?

To fix B3685: Run diagnostics on the SRS system to confirm the error.. Visually inspect the wiring harness and sensor contacts. Check the sensor resistance according to the manual. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B3685?

Do not drive — repair immediately

How much does it cost to fix B3685?

The estimated repair cost for B3685 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat