AutoCodes – Generic – B1878

B1878 Code - Short to Positive in Passenger Side Front Seat Cushion Squib Circuit

Quick Answer

The Front Seat Cushion Squib Right (RH) Circuit consists of the Center Airbag Sensor Assembly and the Front Seat Airbag Sub-Assembly. Common causes include Faulty Front Seat Airbag Sub-Assembly (Front Seat Cushion Squib Right), Front Seat Airbag Sub-Assembly harness is open or shorted, Front Seat Airbag Sub-Assembly 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: B1878 indicates Short to Positive in Passenger Side Front Seat Cushion Squib Circuit.
Common causes: Common causes include Faulty Front Seat Airbag Sub-Assembly (Front Seat Cushion Squib Right), Front Seat Airbag Sub-Assembly harness is open or shorted, Front Seat Airbag Sub-Assembly 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.

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Code Popularity 10,469

How popular is this code, among other codes? Low

Repair Importance Level

Urgent (Diagnose now) (3 / 3)

Repair Difficulty Level

Advanced (Pro) (3 / 3)

What is this?

Table of contents Created and updated by William Orellana on Dec 02, 2022

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1878 Description

The Front Seat Cushion Squib Right (RH) Circuit consists of the Center Airbag Sensor Assembly and the Front Seat Airbag Sub-Assembly. This circuit instructs the Supplemental Restraint System (SRS) to deploy when deployment conditions are met. The Diagnostic Trouble Code (DTC) is stored when a malfunction is detected in the Front Seat Cushion Squib Right (RH).

OBDII Code B1878 - Short to Positive in Passenger Side Front Seat Cushion Squib Circuit - AutoCodes.com — B1878 Code - Short to Positive in Passenger Side Front Seat Cushion Squib Circuit

What does this mean?

What are the Possible Causes of the DTC B1878?

Faulty Front Seat Airbag Sub-Assembly (Front Seat Cushion Squib Right)
Front Seat Airbag Sub-Assembly harness is open or shorted
Front Seat Airbag Sub-Assembly circuit poor electrical connection
Faulty Center Airbag Sensor Assembly

How to Fix the DTC B1878?

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 B1878 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 B1878 code?

Need more information on how to fix the B1878 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1878 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B1878 Ford — Seat Belt Driver Pretensioner Circuit Short To Battery
B1878 Lexus — Short to Positive in Passenger Side Front Seat Cushion Squib Circuit
B1878 Lincoln — Seat Belt Driver Pretensioner Circuit Short To Battery
B1878 Mazda — Seat Belt Driver Pretensioner Circuit Short To Battery
B1878 Mercury — Seat Belt Driver Pretensioner Circuit Short To Battery
B1878 Scion — Short to Positive in Passenger Side Front Seat Cushion Squib Circuit
B1878 Toyota — Short to Positive in Passenger Side Front Seat Cushion Squib Circuit

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 B1878 Code

1. What are the common symptoms of OBDII code B1878 (Short to Positive in Passenger Side Front Seat Cushion Squib Circuit)?

The common symptoms of this code may include an illuminated airbag warning light on the dashboard and potential non-deployment of the passenger side airbag in the event of a collision.

2. What are the possible causes of OBDII code B1878?

Possible causes of this code include a short circuit to the positive terminal in the passenger side front seat cushion squib circuit, faulty wiring, or a malfunctioning airbag control module.

3. How can I diagnose OBDII code B1878?

Diagnosing this code typically involves using a diagnostic scan tool to retrieve the specific fault code, visually inspecting the wiring and connectors in the passenger side front seat area, and performing continuity and resistance tests on the circuit.

4. Can I continue driving with OBDII code B1878 present?

It is not recommended to drive with this code present, as it signifies a potential issue with the passenger side airbag system, which could compromise occupant safety in the event of an accident.

5. How can OBDII code B1878 be repaired?

Repairing this code usually involves identifying and repairing the short circuit to the positive terminal in the passenger side front seat cushion squib circuit, repairing or replacing any damaged wiring, and resetting the airbag system.

6. Is it safe to attempt to repair OBDII code B1878 myself?

Due to the safety implications of airbag system malfunctions, it is recommended to have this code diagnosed and repaired by a qualified automotive technician to ensure the work is done correctly and safely.

7. How much does it typically cost to repair OBDII code B1878?

The cost of repairing this code can vary depending on the specific cause of the issue, the extent of the damage, and the labor rates in your area. It is advisable to obtain estimates from local repair shops.

8. Can OBDII code B1878 be intermittent?

Yes, this code can sometimes be intermittent if the short circuit in the passenger side front seat cushion squib circuit is sporadic. However, it is essential to address the issue promptly to ensure proper airbag functionality.

9. Will OBDII code B1878 reset on its own?

If the underlying issue causing the code is not resolved, it is unlikely to reset on its own. Even if the warning light goes off temporarily, the code may reappear if the fault is not fixed.

10. How long does it take to repair OBDII code B1878?

The repair time for this code can vary depending on the complexity of the issue and the availability of parts. In some cases, the repair may be completed within a few hours, while more involved repairs could take longer.