AutoCodesGeneric – B1939

B1939 Code - Air Bag Passenger Pressure Switch Circuit Short To Ground Fault

Quick Answer

The Restraints Control Module (RCM) monitors the Air Bag Passenger Pressure Switch. Common causes include Faulty Air Bag Passenger Pressure Switch, Air Bag Passenger Pressure Switch harness is open or shorted, Air Bag Passenger Pressure Switch circuit poor electrical connection. Severity is High - diagnose this code as soon as possible. Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.

What it means
B1939 indicates Air Bag Passenger Pressure Switch Circuit Short To Ground Fault.
Common causes
Common causes include Faulty Air Bag Passenger Pressure Switch, Air Bag Passenger Pressure Switch harness is open or shorted, Air Bag Passenger Pressure Switch circuit poor electrical connection.
Severity
High - diagnose this code as soon as possible.
Can I drive?
Driving is not recommended if the warning light is flashing, the engine runs poorly, or safety-related symptoms are present.
AI answers can be wrong. Verify repairs with testing. Open full chat
Code Popularity 3,875
How popular is this code, among other codes? Low
Table of contents Created and updated by William Orellana on Jul 29, 2019
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Code B1939 Description

The Restraints Control Module (RCM) monitors the Air Bag Passenger Pressure Switch. The RCM sets the OBDII code when the Air Bag Passenger Pressure Switch is not to factory specifications.
OBDII Code B1939 - Air Bag Passenger Pressure Switch Circuit Short To Ground Fault - AutoCodes.com
B1939 Code - Air Bag Passenger Pressure Switch Circuit Short To Ground Fault

What are the Possible Causes of the DTC B1939?

  • Faulty Air Bag Passenger Pressure Switch
  • Air Bag Passenger Pressure Switch harness is open or shorted
  • Air Bag Passenger Pressure Switch circuit poor electrical connection
  • Faulty Restraint Control Module (RCM)

How to Fix the DTC B1939?

Review the 'Possible Causes' above and visually examine the corresponding wiring harness and connectors. Check for damaged components and inspect connector pins for signs of being broken, bent, pushed out, or corroded.

What is the Cost to Diagnose the Code?

Labor: 1.0

To diagnose the B1939 code, it typically requires 1.0 hour of labor. Rates vary by location, vehicle, and shop. Many shops charge between $80–$150 per hour; dealerships and metro areas may be higher, independents may be lower.

Need more information about the B1939 code?

Need more information on how to fix the B1939 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1939 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

  • B1939 Ford — Air Bag Passenger Pressure Switch Circuit Short To Ground Fault
  • B1939 Lincoln — Air Bag Passenger Pressure Switch Circuit Short To Ground Fault
  • B1939 Mercury — Air Bag Passenger Pressure Switch Circuit Short To Ground Fault

Precautions for SRS “AIR BAG” and “SEAT BELT PRE-TENSIONER” Service

  • Never probe the electrical connectors on air bag, side air curtain modules or seat belts.
  • Never disassemble or tamper with safety belt buckle/retractor pretensioners, adaptive load limiting retractors, safety belt inflators, or probe the electrical connectors.
  • Do not use electrical test equipment to check SRS circuits unless instructed to in this Service Manual.
  • Before servicing the SRS, turn ignition switch OFF, disconnect both battery cables and wait at least 3 minutes. For approximately 3 minutes after the cables are removed, it is still possible for the air bag and seat belt pre-tensioner to deploy. Therefore, do not work on any SRS connectors or wires until at least 3 minutes have passed.

Failure to follow this instruction may result in the accidental deployment of these modules, which increases the risk of serious personal injury or death.

About the author: William Orellana is a Master Mechanic and Mechanical Engineer with over 30 years of experience diagnosing and repairing vehicles. Learn more about his background.

Frequently Asked Questions about B1939 Code

1. What are common symptoms of OBDII code B1939?

- Common symptoms include the airbag warning light illuminating on the dashboard, the airbag system not functioning properly, and potential loss of passenger-side airbag protection.

2. What causes the B1939 code to indicate an Air Bag Passenger Pressure Switch Circuit Short To Ground Fault?

- The B1939 code is typically triggered by a short circuit to ground in the passenger pressure switch circuit, often caused by damaged wiring, a faulty pressure switch, or a poor connection.

3. How serious is the B1939 code related to the Air Bag Passenger Pressure Switch Circuit Short To Ground Fault?

- This code is serious as it indicates a fault in the passenger-side airbag system, potentially leading to the airbag not deploying in the event of a collision, posing a safety risk to the vehicle occupants.

4. Can I continue driving with the B1939 code present?

- It is not recommended to continue driving with the B1939 code active, as the airbag system's failure to deploy in a crash could increase the risk of injury to passengers.

5. How can I diagnose and repair the B1939 code at home?

- Diagnosing and repairing the B1939 code may require specialized equipment and knowledge. It is advisable to consult a professional mechanic or technician to accurately diagnose and fix the issue.

6. What are the typical repair options for resolving the B1939 code?

- Repair options may include repairing or replacing damaged wiring, replacing the passenger pressure switch, checking and securing connections, and resetting the fault codes using an OBDII scanner.

7. Is it possible to reset the B1939 code without fixing the underlying issue?

- While you can clear the error code temporarily, it is essential to address the root cause of the B1939 code to ensure the airbag system functions correctly and provides adequate safety in case of an accident.

8. Can extreme temperatures or environmental factors trigger the B1939 code?

- Extreme temperatures or environmental conditions can potentially exacerbate existing issues leading to the B1939 code, such as causing wiring insulation to degrade or connections to corrode.

9. Are there any preventive maintenance steps to avoid the B1939 code in the future?

- Regular inspection of the airbag system, checking for any visible damage or wear in wiring and components, and addressing any issues promptly can help prevent the occurrence of the B1939 code.

10. How long does it typically take to repair the B1939 code related to the Air Bag Passenger Pressure Switch Circuit Short To Ground Fault?

- The repair time for the B1939 code can vary depending on the exact cause of the fault and the extent of repairs needed. It is best to consult a professional for an accurate estimate.

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