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AutoCodes - Generic - B0021

B0021 Code - Left Curtain Deployment Control 1

Updated Dec 31, 2018
- Code Popularity: 20,966 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
Table of contents
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|B0021 code possible causes

  • Faulty Driver Side Air Curtain
  • Driver Side Air Curtain harness is open or shorted
  • Driver Side Air Curtain circuit poor electrical connection

|How do I fix code B0021 code?

Check the "Possible Causes" listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector's pins.

|Cost of diagnosing B0021 code

Labor: 1.0

The cost of diagnosing the B0021 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle's make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.

|When is the B0021 code detected?

If the Restraints Control Module (RCM) detects a short between the driver side air curtain circuits and the circuits of another SRS component, it sets this Diagnostic Trouble Code (DTC) and the DTC of the corresponding SRS component.

|What are B0021 code possible symptoms?

  • Air Bag Warning Light ON

|B0021 code description

The Restraints Control Module (RCM) monitors all deployable device and sensor circuits for a signal cross coupled (short) between circuits. If the RCM detects a short between the circuits of one device and another device, it will store a DTC for each of the signal cross coupled faults in memory. The RCM sends a message to the Instrument Panel Cluster (IPC) to illuminate the air bag warning indicator. When a normal loop fault is present (one loop is either shorted to battery/ground, open circuit or low resistance), then signal cross coupled diagnostics will not be active. Once the normal loop fault is repaired, then the signal cross coupled diagnostics will resume.

OBDII Code B0021 - Left Curtain Deployment Control 1 - AutoCodes.com
Left Curtain Deployment Control 1

|Need more information with the B0021 code?

Need more information on how to fix the B0021 code?
Get Access to Factory Service Manuals

|Information for specific makes

|Need help with a B0021 code?

Get the B0021 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.

|B0021 code comments

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