OBD Guide
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B15C4

Airbag Signal Malfunction/Not Input

B15C4 is an OBD-II diagnostic trouble code meaning: Airbag Signal Malfunction/Not Input. Common causes: broken or damaged wiring harness to the airbag, malfunction of the squib in the pillow. Estimated repair cost: $11–278.

Severity
🔴 High
Can you drive?
Do not drive — repair immediately
Approx. repair cost
$11–278 (est.)

Symptoms

  • Airbag light is on
  • Airbags do not work in test mode
  • No communication with the airbag module during diagnostics

Causes

  • Broken or damaged wiring harness to the airbag
  • Malfunction of the squib in the pillow
  • Oxidation of contacts in system connectors
  • Problems with the airbag control module (ACM)

How to Fix

  1. Check the integrity of the wiring harness to the problem airbag
  2. Check the resistance of the squib (usually 2-3 ohms)
  3. Clean the contacts in the system connectors
  4. Scan the ACM module for additional errors
  5. If necessary, replace the airbag or control module

Related codes

B15C5B15C3B1020

FAQ

What does the B15C4 code mean?

B15C4 is an OBD-II diagnostic trouble code that indicates: Airbag Signal Malfunction/Not Input

What causes a B15C4 error code?

The most common causes of B15C4 include: Broken or damaged wiring harness to the airbag; Malfunction of the squib in the pillow; Oxidation of contacts in system connectors; Problems with the airbag control module (ACM).

How do I fix a B15C4 diagnostic trouble code?

To fix B15C4: Check the integrity of the wiring harness to the problem airbag. Check the resistance of the squib (usually 2-3 ohms). Clean the contacts in the system connectors. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B15C4?

Do not drive — repair immediately

How much does it cost to fix B15C4?

The estimated repair cost for B15C4 is $11–278. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat