B3857 Saturn Code - Incorrect Rollover Sensor Installed

Quick Answer

The B3857 diagnostic trouble code for Saturn vehicles indicates that an incorrect rollover sensor has been installed in the vehicle. Common causes include Incorrect installation of a new rollover sensor during repairs or maintenance, Using a faulty or incompatible rollover sensor during repairs, Damage to the rollover sensor due to impact or collision. 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

B3857 Saturn indicates Incorrect Rollover Sensor Installed.

Common causes

Common causes include Incorrect installation of a new rollover sensor during repairs or maintenance, Using a faulty or incompatible rollover sensor during repairs, Damage to the rollover sensor due to impact or collision.

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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• Symptoms
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Common Causes of B3857 Saturn

Symptoms of B3857 Saturn

How to Fix B3857 Saturn

Cost to Fix B3857 Saturn

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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 B3857 Saturn Code

1. What does the OBDII code B3857 mean on a Saturn?

The code B3857 indicates that the vehicle has detected an incorrect or incompatible rollover sensor installed.

2. What are the common symptoms of the B3857 code?

Symptoms may include an illuminated airbag warning light, a malfunctioning rollover protection system, and potential deactivation of safety features.

3. What causes the B3857 code to appear?

The code is typically caused by installing the wrong rollover sensor, a defective sensor, or a software mismatch in the vehicle's control module.

4. Can a faulty rollover sensor trigger the B3857 code?

Yes, a faulty or damaged rollover sensor can cause the code by sending incorrect data to the vehicle's control module.

5. How do I fix the B3857 code on my Saturn?

Fixing the code usually involves verifying the sensor part number, replacing the incorrect or faulty sensor, and possibly updating the vehicle's software.

6. Is it safe to drive a Saturn with the B3857 code active?

While the vehicle may still be drivable, the rollover protection system and certain airbag functions may not operate properly, reducing overall safety.

7. How do I know if the rollover sensor is compatible with my Saturn?

Check the part number on the sensor and compare it with the manufacturer’s specifications for your vehicle model and year.

8. Will disconnecting the battery clear the B3857 code?

Disconnecting the battery may temporarily clear the code, but it will return if the underlying issue with the rollover sensor is not resolved.

9. Can a software update fix the B3857 code?

In some cases, if the issue is due to a software mismatch, updating the control module software may resolve the problem.

10. Do I need a professional to repair the B3857 code?

While some issues, like verifying part numbers, can be done at home, diagnosing and replacing the sensor or updating software may require professional tools and expertise.