OBD Guide
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B172C

Roof Status Signal Trunk

B172C is an OBD-II diagnostic trouble code meaning: Roof Status Signal Trunk. Common causes: open or short circuit in the trunk side curtain circuit, damage to the wiring harness in the trunk area. Estimated repair cost: $56–167.

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

Symptoms

  • Airbag light is on
  • Security check message on dashboard
  • Inactivity of the security system in the luggage compartment during testing

Causes

  • Open or short circuit in the trunk side curtain circuit
  • Damage to the wiring harness in the trunk area
  • Roof/curtain position sensor malfunction
  • SRS unit software error
  • Mechanical damage to the curtain airbag

How to Fix

  1. Diagnose the SRS system using a scanner
  2. Check the integrity of the wiring harness in the trunk
  3. Check connections in side curtain circuit
  4. Test roof position sensors
  5. If necessary, replace faulty elements
  6. Reset errors and test the system

Related codes

B1720B1725B1730

FAQ

What does the B172C code mean?

B172C is an OBD-II diagnostic trouble code that indicates: Roof Status Signal Trunk

What causes a B172C error code?

The most common causes of B172C include: Open or short circuit in the trunk side curtain circuit; Damage to the wiring harness in the trunk area; Roof/curtain position sensor malfunction; SRS unit software error.

How do I fix a B172C diagnostic trouble code?

To fix B172C: Diagnose the SRS system using a scanner. Check the integrity of the wiring harness in the trunk. Check connections in side curtain circuit. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B172C?

Do not drive — repair immediately

How much does it cost to fix B172C?

The estimated repair cost for B172C is $56–167. Actual cost depends on your vehicle, location, and labor rates.

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See also: Russian version · NationStat