OBD Guide

B1780

Front Occupant Classification Sensor Left Circuit Malfunction

B1780 is an OBD-II diagnostic trouble code meaning: Front Occupant Classification Sensor Left Circuit Malfunction. Common causes: open or short circuit in the sensor wiring harness, damage to the passenger classification sensor itself. Estimated repair cost: $56–167.

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

Symptoms

  • Airbag light is on
  • The system can disable the front passenger airbag
  • Possible false alarms of the system

Causes

  • Open or short circuit in the sensor wiring harness
  • Damage to the passenger classification sensor itself
  • Airbag module malfunction
  • Corrosion or poor contact in connectors

How to Fix

  1. Conduct a visual inspection of the sensor wiring harness and connectors
  2. Check the continuity of the sensor circuit using a multimeter
  3. If necessary, replace the passenger classification sensor
  4. Reset the error and check the system operation

Related codes

FAQ

What does the B1780 code mean?

B1780 is an OBD-II diagnostic trouble code that indicates: Front Occupant Classification Sensor Left Circuit Malfunction

What causes a B1780 error code?

The most common causes of B1780 include: Open or short circuit in the sensor wiring harness; Damage to the passenger classification sensor itself; Airbag module malfunction; Corrosion or poor contact in connectors.

How do I fix a B1780 diagnostic trouble code?

To fix B1780: Conduct a visual inspection of the sensor wiring harness and connectors. Check the continuity of the sensor circuit using a multimeter. If necessary, replace the passenger classification sensor. For a complete diagnosis, use an OBD-II scanner.

Is it safe to drive with B1780?

Do not drive — repair immediately

How much does it cost to fix B1780?

The estimated repair cost for B1780 is $56–167. Actual cost depends on your vehicle, location, and labor rates.

See also: Russian version · NationStat