OBD Guide

B2104

Door Passenger Key Cylinder Switch Failure

B2104 is an OBD-II diagnostic trouble code meaning: Door Passenger Key Cylinder Switch Failure. Common causes: oxidation or wear of limit switch contacts, broken wires in the harness between the lock and the control unit. Estimated repair cost: $22–111.

Severity
Low
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$22–111 (est.)

Symptoms

  • False alarm about an open door
  • Inability to unlock the door with a key
  • Comfort closing/opening functions do not work
  • The door ajar indicator lights up when the door is closed

Causes

  • Oxidation or wear of limit switch contacts
  • Broken wires in the harness between the lock and the control unit
  • Short circuit in the limit switch circuit
  • Door control unit malfunction

How to Fix

  1. Check the operation of the limit switch with a multimeter
  2. Inspect the wiring harness for damage
  3. Clean the switch contacts from oxides
  4. If necessary, replace the limit switch or wiring harness
  5. Reset the error code and check if it appears again

Related codes

FAQ

What does the B2104 code mean?

B2104 is an OBD-II diagnostic trouble code that indicates: Door Passenger Key Cylinder Switch Failure

What causes a B2104 error code?

The most common causes of B2104 include: Oxidation or wear of limit switch contacts; Broken wires in the harness between the lock and the control unit; Short circuit in the limit switch circuit; Door control unit malfunction.

How do I fix a B2104 diagnostic trouble code?

To fix B2104: Check the operation of the limit switch with a multimeter. Inspect the wiring harness for damage. Clean the switch contacts from oxides. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B2104?

Limited driving only, diagnose soon

How much does it cost to fix B2104?

The estimated repair cost for B2104 is $22–111. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat