B1939 Mercury Code - Air Bag Passenger Pressure Switch Circuit Short To Ground Fault
Quick Answer
The B1939 diagnostic trouble code for Mercury vehicles indicates an issue with the Air Bag Passenger Pressure Switch Circuit being shorted to ground. Common causes include Faulty passenger pressure switch, Short circuit in the wiring harness, Loose or corroded electrical connections. 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 Mercury indicates Air Bag Passenger Pressure Switch Circuit Short To Ground Fault.
- Common causes
- Common causes include Faulty passenger pressure switch, Short circuit in the wiring harness, Loose or corroded electrical connections.
- 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.
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Code B1939 Mercury Description
The B1939 diagnostic trouble code for Mercury vehicles indicates an issue with the Air Bag Passenger Pressure Switch Circuit being shorted to ground. This circuit is responsible for monitoring the weight of the passenger in the front seat to determine whether the airbag should deploy in the event of a collision. When this circuit is shorted to ground, it can lead to a malfunction in the airbag system, potentially causing the airbag not to deploy when needed or to deploy unexpectedly.
Common Causes of B1939 Mercury
- Faulty passenger pressure switch.
- Short circuit in the wiring harness.
- Loose or corroded electrical connections.
- Damage to the airbag control module.
- Issues with the airbag system's control unit.
Symptoms of B1939 Mercury
- Airbag warning light illuminated on the dashboard.
- Airbag system fault displayed on the instrument cluster.
- Inability to turn off the passenger airbag.
- Intermittent or non-deployment of the passenger airbag.
- Diagnostic trouble code B1939 stored in the vehicle's computer system.
How to Fix B1939 Mercury
- Begin by diagnosing the specific cause of the short to ground fault, using a diagnostic scanner to retrieve the trouble codes and pinpoint the issue.
- Inspect the wiring harness for any signs of damage, corrosion, or loose connections. Repair or replace any damaged wiring as necessary.
- Test the passenger pressure switch to determine if it is functioning correctly. Replace the switch if it is faulty.
- Check the airbag control module for any damage or malfunctions. Replace the module if needed.
- Clear the diagnostic trouble codes from the vehicle's computer system and perform a test to ensure that the issue has been resolved.
Cost to Fix B1939 Mercury
The cost of repairing a B1939 code for a Mercury vehicle can vary depending on the specific cause of the issue and the labor rates in your area. On average, the repair costs for this type of airbag system fault can range from $200 to $500, including parts and labor. It is important to note that diagnostic time and labor rates at auto repair shops can vary, so it is advisable to obtain quotes from multiple shops to ensure a competitive price. Keep in mind that rates may be higher at dealerships or in metropolitan areas, while independent shops often offer more affordable rates.
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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.
Frequently Asked Questions about B1939 Mercury Code
1. What are common symptoms of OBDII code B1939 in a Mercury related to the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault?
- Common symptoms include the airbag warning light illuminating on the dashboard and potential non-deployment of the passenger side airbag in the event of a collision.
2. What causes the OBDII code B1939 in a Mercury for the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault?
- The code B1939 typically occurs due to a short circuit between the passenger pressure switch circuit and ground, which can be caused by damaged wiring or a faulty pressure switch.
3. How can I diagnose the OBDII code B1939 in my Mercury related to the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault?
- Diagnosis involves using an OBDII scanner to retrieve the specific code, inspecting the wiring and connectors for damage, and testing the pressure switch for proper functionality.
4. What are some repair tips for fixing the OBDII code B1939 in a Mercury for the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault?
- Repair tips include repairing or replacing any damaged wiring, ensuring proper connection of the pressure switch, and clearing the fault code with an OBDII scanner after the repair is completed.
5. Is it safe to drive my Mercury with the OBDII code B1939 related to the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault?
- It is not recommended to drive the vehicle with an unresolved airbag system fault, as it can compromise passenger safety in the event of an accident. Prompt repair is advised.
6. Can I reset the OBDII code B1939 in my Mercury related to the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault without fixing the underlying issue?
- While you can clear the fault code with an OBDII scanner, it is important to address the root cause of the issue to ensure the airbag system functions properly and maintains passenger safety.
7. How much does it typically cost to repair the OBDII code B1939 in a Mercury for the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault?
- Repair costs can vary depending on the extent of the damage and whether any components need to be replaced. It is advisable to consult a professional mechanic for an accurate estimate.
8. Can I fix the OBDII code B1939 in my Mercury related to the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault myself?
- While some DIY enthusiasts may be able to address simple wiring issues, diagnosing and repairing airbag system faults can be complex and requires specialized knowledge. Consulting a professional is recommended.
9. Are there any recalls or technical service bulletins related to the OBDII code B1939 in a Mercury for the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault?
- It is advisable to check with the manufacturer or a dealership to see if there are any recalls or technical service bulletins related to this specific OBDII code in your Mercury model.
10. How long does it typically take to repair the OBDII code B1939 in a Mercury for the Air Bag Passenger Pressure Switch Circuit Short to Ground Fault?
- The repair time can vary depending on the extent of the issue and the availability of parts. Simple repairs may take a few hours, while more complex issues could require a day or more.
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