OBD Guide
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B2390

Mist Switch Circuit Low

B2390 is an OBD-II diagnostic trouble code meaning: Mist Switch Circuit Low. Common causes: open or short circuit in wiring, faulty fog light switch. Estimated repair cost: $56–167.

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

Symptoms

  • Fog lights don't turn on
  • Flashing fog lights
  • Fog switch does not respond to presses

Causes

  • Open or short circuit in wiring
  • Faulty fog light switch
  • Poor contact in connectors
  • Problems with fog light relay
  • Control unit malfunction

How to Fix

  1. Check the continuity of the wiring in the fog switch circuit
  2. Check the condition of the fog light switch
  3. Clean connector contacts
  4. Check the fog lamp relay
  5. Scan the control unit for other errors

Related codes

B2391B2392

FAQ

What does the B2390 code mean?

B2390 is an OBD-II diagnostic trouble code that indicates: Mist Switch Circuit Low

What causes a B2390 error code?

The most common causes of B2390 include: Open or short circuit in wiring; Faulty fog light switch; Poor contact in connectors; Problems with fog light relay.

How do I fix a B2390 diagnostic trouble code?

To fix B2390: Check the continuity of the wiring in the fog switch circuit. Check the condition of the fog light switch. Clean connector contacts. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B2390?

Do not drive — repair immediately

How much does it cost to fix B2390?

The estimated repair cost for B2390 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat