OBD-II code · Body

B0100 Driver Door Lock Cylinder Switch Circuit

The body control module has detected a fault in the driver door lock cylinder switch circuit. This switch detects key rotation in the door lock and is used for keyless functions and the alarm system.

Is it safe to drive with B0100?

Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.

Common causes

  • Most likelyLock cylinder switch failed
  • PossibleDoor harness broken in door hinge area

Symptoms

  • Warning light or symbol related to the affected system
  • Comfort or safety function impaired

Repair at a glance

Difficulty
Medium
DIY friendly
Often, with basic tools
Typical labour
0.5–2 h
Emissions test
Usually unaffected
Parts involved
Door Lock Cylinder Switch, Body Control Module, Door Harness

Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.