B0391 - DTC B0391 - Understanding the Airbag Sensor Malfunction in 2010-2018 Ford Fusions and Other Vehicles

Quick Answer

B0391 means: B0391 indicates a malfunction in the airbag passenger sensor, potentially disabling the airbag system.

Fix: Check and replace faulty components Cost: $100 - $300 Time: 90-180 minutes

Can I drive with B0391? Immediate attention is recommended to ensure passenger safety.

Common Questions

What does B0391 mean and how does it affect my car?

B0391 indicates a malfunction in the passenger airbag sensor, which can disable the airbag system. This poses a significant safety risk as the airbags may not deploy in an accident, increasing the potential for injury.

What are the most common causes of B0391 and how much does it cost to fix?

Common causes include a faulty airbag sensor, damaged wiring, or issues with the airbag control module. Repair costs range from $50 to $300, depending on the specific issue and parts needed.

Can I drive my car with B0391 or should I stop immediately?

It is not safe to drive your vehicle with a B0391 code active. You should address this issue immediately, as it could prevent airbags from deploying during a collision.

How can I diagnose B0391 myself using GeekOBD APP?

To diagnose B0391, use the GeekOBD APP to scan for codes. Look for the specific B0391 code and any freeze frame data that may provide additional context regarding when the fault occurred.

What vehicles are most commonly affected by B0391?

B0391 is commonly seen in vehicles like the Ford Fusion (2010-2018), Ford Focus (2012-2018), and other models equipped with similar airbag systems.

How can I prevent B0391 from happening again?

Regular maintenance of your vehicle's electrical system, including checks for corrosion and proper connections, can help prevent B0391 from reoccurring.

What is B0391?

Diagnostic Trouble Code (DTC) B0391 indicates a malfunction in the airbag system, specifically relating to the passenger airbag sensor. This code typically surfaces when the vehicle's onboard diagnostic system detects an issue with the sensor's performance or its connection to the airbag control module. When B0391 is triggered, it can lead to the airbag system being disabled, which means that in the event of an accident, the airbags may not deploy, putting the safety of occupants at risk. Commonly found in vehicles like the 2010-2018 Ford Fusion, this code often results from poor electrical connections, damaged wiring, or a faulty sensor itself. Real-world implications include illuminated warning lights on the dashboard, which serve as a reminder to drivers that there is a critical issue with the airbag system. It’s essential to address B0391 promptly, as ignoring it could lead to severe consequences during an accident. Additionally, it can also affect the vehicle’s insurance coverage, as many policies require all safety systems to be fully operational for claims to be honored. Therefore, understanding B0391 is crucial for any car owner, especially for those with families or frequent passengers.

System: B - Body (Airbags, Lighting, Security, Climate Control)

Symptoms

Common symptoms when B0391 is present:

The airbag warning light on the dashboard remains illuminated, signaling a fault in the airbag system.
A noticeable delay in the airbag deployment during tests or diagnostics, indicating possible sensor issues.
The vehicle may exhibit erratic behavior with other electronic systems due to electrical interference, affecting overall driving experience.
Inconsistent warning messages on the dashboard regarding airbag readiness, creating confusion for the driver.
Failure of the airbag to deploy during a simulated test, confirming the seriousness of the B0391 fault.

Possible Causes

Most common causes of B0391 (ordered by frequency):

{'cause': 'Faulty passenger airbag sensor', 'likelihood': '60%', 'details': 'The sensor may have malfunctioned due to wear and tear, especially in older models.'}
{'cause': 'Damaged wiring or connectors', 'details': 'Corroded or broken wires can interrupt the signal between the sensor and the control module.'}
{'cause': 'Faulty airbag control module', 'prevention': 'Regular system checks can help detect issues early before they escalate.'}
{'cause': 'Software issues within the airbag system', 'details': 'Outdated software may lead to incorrect readings from the sensors.'}
{'cause': 'Environmental factors, such as moisture', 'details': 'Water ingress can damage electronic components, leading to sensor failure.'}

B0391 Repair Costs

Cost Breakdown by Repair Type

Sensor Replacement

Replacing the faulty passenger airbag sensor which is the most common fix for B0391.

Total: $100 - $300
Success rate: 85%

Wiring Repair

Repairing or replacing damaged wiring and connectors that connect to the airbag system.

Total: $50 - $150
Success rate: 75%

Money-Saving Tips for B0391

Start with the most common and least expensive repairs first
Use GeekOBD APP to confirm diagnosis before replacing expensive parts
Consider preventive maintenance to avoid future occurrences
Compare prices for OEM vs aftermarket parts based on your needs
Address the issue promptly to prevent more expensive secondary damage

Diagnostic Steps

Professional B0391 Diagnosis Process

Follow these systematic steps to accurately diagnose B0391. Each step builds on the previous one to ensure accurate diagnosis.

Step 1: Step 1: Perform an initial visual inspection - Examine the wiring and connectors related to the passenger airbag sensor for signs of damage or corrosion (5-10 minutes)

Step 1: Perform an initial visual inspection - Examine the wiring and connectors related to the passenger airbag sensor for signs of damage or corrosion (5-10 minutes).