Skip the auto shop - Our mechanics make house calls

B1938 OBD-II Trouble Code: Air Bag Passenger Circuit Short to Ground

diagnostic check engine light

B1938 code definition

The B1938 code is manufacturer-specific (in this case General Motors) 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.

What the B1938 code means

A code B1938 will be stored when the ECM has detected a resistance signal other than 1.4-2.9 ohms in the passenger-side air bag module circuit. In addition, the wiring harness between the passenger-side air bag module and SAS control module may have noted a fault or malfunction.

What causes the B1938 code?

Several problems may cause a B1938 code including:

  • Open or short circuit in the wiring harness between the passenger-side air bag module
  • Passenger-side air bag module malfunction
  • SAS control module malfunction

What are the symptoms of the B1938 code?

Symptoms of a B1938 code may include:

  • The check engine or service engine soon light may illuminate
  • Air bag light may incorrectly illuminate
  • Air bag light may flash
  • Passenger-side air bag may not inflate during a crash
  • There may be no symptoms other than a stored B1938 code

How does a mechanic diagnose the B1938 code?

A mechanic may use several methods to diagnose a B1938 trouble code, including:

  • Utilize an OBD-II scanner to check for a stored B1938 trouble code
  • Visually inspect the system for obvious signs of damage or wear
  • Inspect the passenger-side air bag module
  • Inspect the passenger-side air bag module connector
  • Check to see if the malfunction is in the passenger-side air bag module or related wiring harness
  • Inspect the SAS control module

Common mistakes when diagnosing the B1938 code

Note that listed detection conditions are for understanding the DTC outline before performing an inspection. Performing an inspection according to only the detection conditions may cause injury due to an operating error, or damage the system. When performing an inspection, it is recommended to always follow the inspection procedure.

How serious is the B1938 code?

Because a vehicle’s safe driving operation can be impacted due to faults that store a B1938 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 B1938 code?

Several repairs can fix a B1938 trouble code and include:

Additional information related to a B1938 code

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 anyone who may be around you. Always read the service warnings and cautions before handling any air bag system components.

Remember, anything related to air bags can be both difficult and dangerous, and is often best left to professionals for diagnosis and repair. If making any repairs yourself, it is recommended to take care with the air bags when removed from the vehicle and store in a safe place.

Need help with a B1938 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 to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed Related Trouble Codes: P2441: EVAP Vent Valve Stuck Open EVAP trouble...
Auto Safety Tips
Driving is more than a way to get from point A to point B. Owning and driving a car can also be a highly enjoyable experience. Whether a person is driving...


Related questions

Q: Check engine light is illuminated and the car is not starting

Hey there, thanks for writing in. In the future, please include the code number. There are several codes that this system can set. If you have a crank sensor code, this will cause your car to not start. The...

Q: The Check Engine Light comes back on after I reset it

When the Check Engine Light comes on without any specific warning, this can indicate a variety of possible issues. Unfortunately, without more specific symptoms, this can be tough to diagnose without the use of a scanning tool and the skill...

Q: What means error fault code p1978

The trouble code you listed is a manufacturer specific code, designated by the P1xxx. I have searched my files and cant find that DTC trouble code. Can you please verify that the code is P1978? However, if you'd like to...