Skip the auto shop - Our mechanics make house calls

B1939 OBD-II Trouble Code: Air Bag Passenger Pressure Switch Circuit Short to Ground

diagnostic check engine light

B1939 code definition

The B1939 code is manufacturer-specific body code related to air bags. In this case, it means that the engine control module (ECM) has detected a fault with the passenger-side air bag pressure switch.

What the B1939 code means

A code B1939 will be stored when the ECM has detected a short to ground from the passenger-side air bag pressure switch.

What causes the B1939 code?

Several problems may cause a B1939 code including:

  • Damaged or corroded electrical wiring and related components
  • Damaged or defective passenger-side air bag pressure switch
  • Passenger-side air bag module malfunction
  • SAS control module malfunction

What are the symptoms of the B1939 code?

Symptoms of a B1939 code may include:

  • Check engine light may illuminate
  • Air bag light may incorrectly illuminate
  • Air bag light may flash
  • Passenger-side air bags may not inflate
  • There may be no symptoms other than a stored B1939 code

How does a mechanic diagnose the B1939 code?

A mechanic may use several methods to diagnose a B1939 trouble code, including:

  • Utilize an OBD-II scanner to check for a stored B1939 trouble code
  • Visually inspect wiring and related electrical components for signs of damage, wear, or corrosion
  • Inspect the passenger-side air bag module connector
  • Inspect the passenger-side air bag pressure switch
  • Inspect the wiring harness between the SAS control module and clock spring for short to the power supply
  • Inspect passenger-side air bag module
  • Perform SAS control module DTC inspection

Common mistakes when diagnosing the B1939 code

Due to the danger involved with repairing most items related to a vehicle’s air bag system, it is recommended to seek assistance from a professional for repair. If performing repairs yourself, be sure to follow all possible safety precautions and procedures.

How serious is the B1939 code?

Because a vehicle’s safe driving operation can be impacted due to faults that store a B1939 code, this code is considered a potentially serious code. When this code appears, it is recommended to immediately take your vehicle to your local service center or mechanic for repair and diagnosis.

What repairs can fix the B1939 code?

Several repairs can fix a B1939 trouble code and include:

Additional information related to a B1939 code

It cannot be stressed enough that improperly handling a vehicle’s air bag system components can accidentally deploy the air bag modules and pre-tensioner seat belts, which can seriously injure you and others in the vicinity. Read all service warnings and cautions before handling air bag system components. Anything related to air bag repairs can be both difficult and dangerous, and is often best left to professionals for diagnosis and repair. If making any repairs at home, take care with the air bags when removed from the vehicle.

Need help with a B1939 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
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

How Long Does a Vacuum Brake Booster Check Valve Last?
The braking system on your car requires a lot of pressure. The vacuum booster is one of the main sources of this pressure. This booster will take the pressure that...
P0240 OBD-II Trouble Code: Turbocharger Boost Sensor B Circuit Range/Performance
P0240 code definition Turbocharger Boost Sensor B Circuit Range/Performance What the P0240 code means P0240 is an OBD-II generic code triggered when the Engine Control Module (ECM) detects the intake boost...
The Traveler’s Guide to Driving in Malaysia
CraigBurrows / Shutterstock.com Malaysia is a popular destination for many tourists today. The country has amazing sights and attractions that you will want to explore....


Related questions

Q: Code for pressure solenoid D

The P2716 code is produced when the ECM has detected that the throttle body actuator motor has failed to read the correct position at which the butterfly valve within the throttle body should be in order to produce a smooth...

Q: Advice on buying a scan tool

No, I can't think of one that would go for under 500 dollars. If you are talking about the ones that are bi-directional and have a built-in scope, these things start at 1,500 up to 12,000 dollars. For the scopes,...

Q: Code P0303 cylinder 3 misfire

The symptoms you describe along with the blinking Check Engine Light and P0303 trouble code definitely tell us that you have a misfire in cylinder number 3. Your engine uses a coil on plug system. This means each individual...