AutoCodes – Generic – B1021

B1021 Code - Occupant Sensor Control Unit

Quick Answer

The Occupant Sensor Control Unit suppresses the deployment of passenger air bag when the condition of the passenger seat is empty or child and child-seat. Common causes include Faulty Occupant Sensor Control Unit, Occupant Sensor Control Unit harness is open or shorted, Occupant Sensor Control Unit 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: B1021 indicates Occupant Sensor Control Unit.
Common causes: Common causes include Faulty Occupant Sensor Control Unit, Occupant Sensor Control Unit harness is open or shorted, Occupant Sensor Control Unit 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 16,059

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 Mar 11, 2021

Description
Possible Causes
How To Fix
Cost to Diagnose
FAQs
Comments
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Code B1021 Description

The Occupant Sensor Control Unit suppresses the deployment of passenger air bag when the condition of the passenger seat is empty or child and child-seat. And turns on the cut-off telltale lamp when the condition of the passenger seat is child-seat and child. In the case of malfunction, the blinking of the SRS air bag warning lamp reports the malfunction to the driver and by the on board self-diagnosis system. This Occupant Sensor Control Unit classifies occupant in the passenger seat and detects electrical malfunctions in Occupant Classification System, and transmits malfunction information to air bag control unit.
It is integrated into the seat sensor mat and detects the occupants with Occupant Classification System (OCS) control unit that classifies the occupants.

OBDII Code B1021 - Occupant Sensor Control Unit - AutoCodes.com — B1021 Code - Occupant Sensor Control Unit

What does this mean?

What are the Possible Causes of the DTC B1021?

Faulty Occupant Sensor Control Unit
Occupant Sensor Control Unit harness is open or shorted
Occupant Sensor Control Unit circuit poor electrical connection
Faulty Diagnosis Sensor Unit

How to Fix the DTC B1021?

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 B1021 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 B1021 code?

Need more information on how to fix the B1021 code? Get Access to Factory Service Manuals

Need Help with the Code?

Get the B1021 code diagnosed by a professional: Find a repair shop in your area

Information for Specific Makes

B1021 Infiniti — Occupant Sensor Control Unit
B1021 Nissan — Occupant Sensor Control Unit

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 B1021 Code

1. What are common symptoms of OBDII code B1021 related to the Occupant Sensor Control Unit?

The common symptoms include the airbag warning light illuminating on the dashboard and potential issues with the airbag system's functionality.

2. What are the typical causes of OBDII code B1021 related to the Occupant Sensor Control Unit?

The code B1021 is often triggered by a malfunction in the Occupant Sensor Control Unit, which can be caused by wiring issues, sensor failures, or problems with the control unit itself.

3. How serious is OBDII code B1021 related to the Occupant Sensor Control Unit?

This code indicates a problem with the occupant sensor in the vehicle's airbag system, which can compromise the effectiveness of the airbags in the event of a collision. It is important to address this issue promptly to ensure proper airbag functionality.

4. Can OBDII code B1021 related to the Occupant Sensor Control Unit be fixed at home?

While some DIY enthusiasts may attempt to address this code at home, it is recommended to consult a professional mechanic or dealership to accurately diagnose and repair the underlying issue for optimal safety.

5. How is OBDII code B1021 related to the Occupant Sensor Control Unit typically diagnosed?

Diagnosing this code usually involves using a scan tool to retrieve the specific fault code, followed by inspecting the wiring, sensors, and control unit associated with the occupant sensor system to pinpoint the exact cause of the issue.

6. Are there any repair tips for fixing OBDII code B1021 related to the Occupant Sensor Control Unit?

Repair tips may include checking and repairing any damaged wiring, replacing faulty sensors or the Occupant Sensor Control Unit, and ensuring all connections are secure and functioning properly.

7. What are the potential risks of ignoring OBDII code B1021 related to the Occupant Sensor Control Unit?

Ignoring this code can lead to compromised airbag functionality, increasing the risk of injury in the event of a collision. It is crucial to address airbag system issues promptly for passenger safety.

8. Is it safe to drive with OBDII code B1021 related to the Occupant Sensor Control Unit illuminated?

While the vehicle may still be operable with this code present, it is not advisable to drive without addressing the underlying airbag system issue. Continued driving without proper airbag functionality can pose a safety risk.

9. How much does it typically cost to repair OBDII code B1021 related to the Occupant Sensor Control Unit?

The cost of repair can vary depending on the exact cause of the issue, the extent of the damage, and the labor rates of the repair shop. It is recommended to obtain quotes from different sources for an accurate estimate.

10. Can resetting the OBDII system clear OBDII code B1021 related to the Occupant Sensor Control Unit?

Resetting the OBDII system may temporarily clear the code, but if the underlying issue is not addressed, the code is likely to reappear. It is essential to diagnose and repair the root cause of the problem to prevent the code from returning.