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

Quick Answer

The B1878 Scion code indicates a short to positive in the passenger side front seat cushion squib circuit. Common causes include Wiring harness damage or short circuit, Faulty passenger side front seat cushion squib, Corrosion or poor connections in the circuit. 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 Scion indicates Short to Positive in Passenger Side Front Seat Cushion Squib Circuit.

Common causes

Common causes include Wiring harness damage or short circuit, Faulty passenger side front seat cushion squib, Corrosion or poor connections in the circuit.

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.

• Description
• Common Causes
• Symptoms
• How To Fix
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Common Causes of B1878 Scion

Symptoms of B1878 Scion

How to Fix B1878 Scion

Cost to Fix B1878 Scion

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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.

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 Scion Code

1. What does the OBDII code B1878 mean on a Scion?

B1878 indicates a "Short to Positive" issue in the passenger side front seat cushion squib circuit, which is part of the airbag system.

2. What are the symptoms of code B1878 in a Scion?

Common symptoms include an illuminated airbag warning light on the dashboard and possible deactivation of the passenger airbag.

3. What causes the B1878 code to appear in a Scion?

This code is typically caused by damaged wiring, a short circuit, a faulty seat cushion squib, or a malfunctioning airbag control module.

4. Is it safe to drive with the B1878 code active?

Driving with this code is not recommended as it indicates an issue with the airbag system, which may not deploy correctly in an accident.

5. How can I diagnose the B1878 code in a Scion?

Diagnosis involves inspecting the wiring and connectors under the passenger seat for damage, testing the squib circuit resistance, and checking for shorts to positive voltage.

6. Can I clear the B1878 code without fixing the issue?

Clearing the code without repairing the underlying issue will only temporarily remove the warning, and the code will likely return.

7. How much does it cost to fix the B1878 code in a Scion?

Repair costs vary but can range from $100 for simple wiring repairs to over $500 if the seat squib or airbag control module needs replacement.

8. Can a loose connector cause the B1878 code?

Yes, a loose or corroded connector in the passenger seat squib circuit can trigger this code.

9. Do I need special tools to fix the B1878 code?

Special tools like a scan tool with airbag system diagnostics and a multimeter are often required for proper diagnosis and repair.

10. What should I do if the B1878 code persists after repairs?

If the code persists, recheck all connections, verify the integrity of the wiring, and consider having the airbag control module tested by a professional.