OBD Guide
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B1209

Frontal Collision Detection

B1209 is an OBD-II diagnostic trouble code meaning: Frontal Collision Detection. Common causes: front impact sensor malfunction, open or short circuit in wiring harness. Estimated repair cost: $56–278.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$56–278 (est.)

Symptoms

  • Airbag light is on
  • The passive safety system is not activated during testing
  • The error persists after being reset by the scanner

Causes

  • Front impact sensor malfunction
  • Open or short circuit in wiring harness
  • Damage to the airbag control unit
  • Corrosion of contacts in system connectors
  • Previous accident without proper system repair

How to Fix

  1. Check fault codes with a scanner (ABS and SRS)
  2. Inspect the shock sensors and their connections
  3. Check the integrity of the system wiring harness
  4. Test the resistance of the squibs
  5. If necessary, replace faulty components
  6. Programmatically reset the error after repair

Related codes

B1200B1201B1210B1211

FAQ

What does the B1209 code mean?

B1209 is an OBD-II diagnostic trouble code that indicates: Frontal Collision Detection

What causes a B1209 error code?

The most common causes of B1209 include: Front impact sensor malfunction; Open or short circuit in wiring harness; Damage to the airbag control unit; Corrosion of contacts in system connectors.

How do I fix a B1209 diagnostic trouble code?

To fix B1209: Check fault codes with a scanner (ABS and SRS). Inspect the shock sensors and their connections. Check the integrity of the system wiring harness. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1209?

Do not drive — repair immediately

How much does it cost to fix B1209?

The estimated repair cost for B1209 is $56–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat