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B1905 OBD-II Trouble Code: Air Bag Crash Sensor #2 Feed/Return Circuit Short to Battery

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B1905 code definition

The B1905 trouble code suggests an error with the airbag crash sensor #2 circuit.

What the B1905 code means

The B1905 code is a generic OBD-II trouble code that detects a circuit problem from the #2 airbag crash sensor. The #2 crash sensor is one of multiple sensors that detect when a vehicle experiences high speed impact, so that the airbags can be deployed. Different makes and models have different numbers of crash sensors, with different locations throughout the front and side of the vehicle, so the placement of the #2 sensor will vary by car. If the airbag control module, body control module, or powertrain control module (PCM) detect an abnormal reading from the #2 airbag crash sensor circuit, then the B1905 trouble code may be stored.

What causes the B1905 code?

The most common cause of the B1905 trouble code is damaged electrical components in the airbag crash sensor system. Shorted wires, blown fuses, corroded connectors, and open circuits are all fairly common. The code is also commonly caused by a malfunctioning #2 airbag crash sensor. In rare cases, the code may be triggered due to the failure of the airbag control module, body control module, or PCM.

What are the symptoms of the B1905 code?

A vehicle with a detected B1905 trouble code will likely have an illuminated check engine soon Warning Light on the instrument panel, and possibly an illuminated airbag Warning Light as well. In most cases, the airbag system will not work properly, so the airbags will likely not be inflated if the vehicle is in a crash.

How does a mechanic diagnose the B1905 code?

The B1905 code will be diagnosed using a standard OBD-II trouble code scanner. A reputable mechanic will use the scanner to view the freeze frame data and assess the B1905 code. Additional trouble codes will also be checked for by the technician and, if noted, will be diagnosed in the order that the scanner shows them in. The trouble codes will then be reset, the vehicle restarted, and the B1905 code checked for again. If the code is no longer detected, then it was likely erroneously triggered, or the result of an intermittent issue.

If the code is still detected, then a visual inspection will be performed on the base electrical components in the system, and any damaged fuses, connectors, and wires will be replaced. The circuit will then be tested, and then the #2 airbag crash sensor will be inspected.

After the mechanic replaces any components, the trouble codes will again be reset, the vehicle restarted, and the code searched for. By doing this, the technician will know as soon as the B1905 code has gone away, and the issue has been fixed.

Common mistakes when diagnosing the B1905 code

The most frequently made mistake when diagnosing this code comes from a failure to properly abide by the OBD-II trouble code diagnosis protocol. It’s important for the diagnosis protocol to always be followed, so that all inspections are efficient, thorough, and accurate.

Functional airbag crash sensors are frequently replaced unnecessarily because damaged electrical components were not inspected.

How serious is the B1905 code?

A vehicle with the B1905 trouble code will not experience any drivability problems. However, the airbag system will likely not work, so the airbags may not deploy should an accident occur. Airbags are highly important safety features that can save the life of a driver and passengers. Because of this, the vehicle should not be driven until it has been inspected and repaired.

What repairs can fix the B1905 code?

Repairs for the B1905 trouble code are:

  • Replacement of the #2 airbag crash sensor circuit
  • Replacement of wires, connectors, and fuses
  • Replacement of the #2 airbag crash sensor
  • In very rare cases, replacement of the PCM, body control module, or airbag control module

Additional comments for consideration regarding the B1905 code

The B1905 code is a manufacturer specific trouble code. This means that, while the code signals a #2 airbag crash sensor circuit error in some makes and models, it may have an entirely different definition for other makes and models. Mechanics should always take into consideration the vehicle that they are inspecting when diagnosing this code.

Need help with a B1905 code?

YourMechanic offers certified mobile mechanics who will come to your home or office to diagnose and repair your vehicle. Get a quote and book an appointment online or speak to a service advisor at 1-800-701-6230.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

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