B0021 BUICK - Passenger Seat Side Air Bag Deployment Loop
Repair Importance Level:
Repair Difficulty Level:
Possible causes
- 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)
Tech notes
DTC B0021 01: Passenger Seat Side Air Bag Deployment Loop Short to BatteryDTC B0021 02: Passenger Seat Side Air Bag Deployment Loop Short to Ground
DTC B0021 04: Passenger Seat Side Air Bag Deployment Loop Open Circuit
DTC B0021 0D: Passenger Seat Side Air Bag Deployment Loop Resistance Above Threshold
DTC B0021 0E: Passenger Seat Side Air Bag Deployment Loop Resistance Below Threshold
Possible symptoms
- Air Bag Warning Light ON
B0021 Buick Description
If a malfunction is detected, a Diagnostic Trouble Code (DTC) will be stored in non-volatile memory. 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.
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.