Engine-Codes - GMC - B0021 GMC

B0021 GMC Code - Passenger Seat Side Air Bag Deployment Loop

- Code Popularity: 8,535 Views
- Repair Importance Level: 3/3
- Repair Difficulty Level: 3/3
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What are the Possible Causes of the Code B0021 GMC?

  • Faulty Passenger Seat Side Air Bag
  • Passenger Seat Side Air Bag harness is open or shorted
  • Passenger Seat Side Air Bag circuit poor electrical connection
  • Faulty Sensing and Diagnostic Module (SDM)

How to Fix the B0021 GMC Code?

Start by checking 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.

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Code B0021 GMC Tech Notes

B0021:01 Passenger Seat Side Air Bag Deployment Loop Short to Battery
B0021:02 Passenger Seat Side Air Bag Deployment Loop Short to Ground
B0021:04 Passenger Seat Side Air Bag Deployment Loop Open
B0021:0D Passenger Seat Side Air Bag Deployment Loop High Resistance
B0021:0E Passenger Seat Side Air Bag Deployment Loop Low Resistance

What is the Cost to Diagnose the Code B0021 GMC?

Labor: 1.0

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

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What are Code B0021 GMC Possible Symptoms?

  • Air Bag Warning Light ON

What Does the B0021 GMC Code Mean?

A Diagnostic Trouble Code (DTC) will be stored in non-volatile memory if a malfunction is detected. During a side or frontal crash of sufficient force, the inflatable restraint Sensing and Diagnostic Module (SDM) will allow current to flow through the deployment loop in order to deploy the passenger seat side air bag. The SDM performs continuous diagnostic tests on the deployment loops to check for proper circuit continuity and for shorts to ground or voltage. A shorting bar is used within the passenger seat side air bag connector which will short together both high and low circuits when the connector is disconnected. This will help to prevent unwanted deployment of the air bag during servicing.

B0021 GMC Code - Passenger Seat Side Air Bag Deployment Loop

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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.

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