AutoCodes – Lexus – B1858 Lexus

B1858 Lexus Code - Short To Positive In Rear Side Squib Left Circuit

Quick Answer

The Rear Side Squib Left (LH) Circuit consists of the Center Airbag Sensor Assembly and the Rear Seat Side Airbag Assembly Left (LH). Common causes include Faulty Rear Seat Side Airbag Assembly Left (LH) (Rear Side Squib Left Circuit), Rear Seat Side Airbag Assembly Left harness is open or shorted, Rear Seat Side Airbag Assembly Left 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: B1858 Lexus indicates Short To Positive In Rear Side Squib Left Circuit.
Common causes: Common causes include Faulty Rear Seat Side Airbag Assembly Left (LH) (Rear Side Squib Left Circuit), Rear Seat Side Airbag Assembly Left harness is open or shorted, Rear Seat Side Airbag Assembly Left 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 773

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 Jul 08, 2019

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1858 Lexus Description

The Rear Side Squib Left (LH) Circuit consists of the Center Airbag Sensor Assembly and the Rear Seat Side Airbag Assembly Left (LH). The 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 Rear Side Squib Left Circuit.

OBDII Code B1858 Lexus - Short To Positive In Rear Side Squib Left Circuit - AutoCodes.com — B1858 Lexus Code - Short To Positive In Rear Side Squib Left Circuit

What does this mean?

What are the Possible Causes of the DTC B1858 Lexus?

Faulty Rear Seat Side Airbag Assembly Left (LH) (Rear Side Squib Left Circuit)
Rear Seat Side Airbag Assembly Left harness is open or shorted
Rear Seat Side Airbag Assembly Left circuit poor electrical connection
Faulty Center Airbag Sensor Assembly

How to Fix the DTC B1858 Lexus?

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 B1858 Lexus 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 B1858 Lexus code?

Need more information on how to fix the B1858 Lexus code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1858 Lexus code diagnosed by a professional: Find a repair shop in your area

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 B1858 Lexus Code

1. What are the common symptoms of OBDII code B1858 in a Lexus related to a short to positive in the rear side squib left circuit?

The common symptoms include the airbag warning light staying illuminated on the dashboard and potential issues with the left side airbag system.

2. What are some possible causes of OBDII code B1858 in a Lexus indicating a short to positive in the rear side squib left circuit?

Potential causes include damaged wiring, a faulty squib (airbag) module, a poor electrical connection, or a blown fuse in the circuit.

3. How can I diagnose OBDII code B1858 in my Lexus related to a short to positive in the rear side squib left circuit?

Diagnosis typically involves using a scan tool to retrieve the specific fault code, inspecting the wiring and connections in the left side airbag circuit, and testing the squib module for proper functionality.

4. Is it safe to drive my Lexus with OBDII code B1858 indicating a short to positive in the rear side squib left circuit?

It is not recommended to drive the vehicle with this fault code present, as it may affect the proper deployment of the airbag in the event of a collision.

5. How can I repair OBDII code B1858 in my Lexus related to a short to positive in the rear side squib left circuit?

Repair options may include repairing or replacing damaged wiring, replacing the faulty squib module, ensuring proper electrical connections, and resetting the fault code with a scan tool.

6. Can I reset OBDII code B1858 in my Lexus indicating a short to positive in the rear side squib left circuit myself?

While you can attempt to reset the fault code using a scan tool, it is important to address the underlying issue causing the code to prevent it from recurring.

7. Are there any safety precautions to consider when working on OBDII code B1858 in a Lexus involving a short to positive in the rear side squib left circuit?

It is crucial to disconnect the vehicle's battery before working on any airbag-related components to avoid accidental deployment and ensure safety.

8. What should I do if OBDII code B1858 keeps returning in my Lexus despite repairs?

If the fault code persists after repairs, consider seeking assistance from a professional technician or dealership to diagnose and address the issue accurately.

9. How much does it typically cost to repair OBDII code B1858 in a Lexus related to a short to positive in the rear side squib left circuit?

The cost of repair can vary depending on the specific cause of the issue, but it may involve expenses for parts, labor, and diagnostic services.

10. Can OBDII code B1858 in a Lexus indicating a short to positive in the rear side squib left circuit affect the overall safety of the vehicle?

Yes, this fault code can impact the proper functioning of the airbag system, potentially compromising the safety of the vehicle's occupants in the event of a collision.