OBD Guide

B12C4

Mirror Turn Indicator Circuit Short

B12C4 is an OBD-II diagnostic trouble code meaning: Mirror Turn Indicator Circuit Short. Common causes: short circuit in the mirror turn signal wiring, malfunction of the turn signal itself. Estimated repair cost: $22–89.

Severity
⚠️ Medium
Can you drive?
Limited driving only, diagnose soon
Approx. repair cost
$22–89 (est.)

Symptoms

  • The turn signal on the side mirror does not work
  • Flashing of all direction indicators at an increased frequency
  • Turn signal fuse blown

Causes

  • Short circuit in the mirror turn signal wiring
  • Malfunction of the turn signal itself
  • Damage to the wiring harness in the doorway
  • Oxidation of contacts in connectors

How to Fix

  1. Check the turn signal fuse
  2. Visually inspect the wiring and connectors of the mirror turn signal
  3. Check continuity with a multimeter
  4. If necessary, replace the turn signal or damaged wires
  5. Clean oxidized contacts

Related codes

FAQ

What does the B12C4 code mean?

B12C4 is an OBD-II diagnostic trouble code that indicates: Mirror Turn Indicator Circuit Short

What causes a B12C4 error code?

The most common causes of B12C4 include: Short circuit in the mirror turn signal wiring; Malfunction of the turn signal itself; Damage to the wiring harness in the doorway; Oxidation of contacts in connectors.

How do I fix a B12C4 diagnostic trouble code?

To fix B12C4: Check the turn signal fuse. Visually inspect the wiring and connectors of the mirror turn signal. Check continuity with a multimeter. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B12C4?

Limited driving only, diagnose soon

How much does it cost to fix B12C4?

The estimated repair cost for B12C4 is $22–89. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat