The B0020 fault code, applicable to all car manufacturers, means “Left Side Airbag Deployment Control (Subfault)“.
Background Information: Side airbags are mainly divided into two categories: side torso airbags and side curtain airbags. Side torso airbags deploy from the seat or door panel to protect the occupant’s torso. Head protection is provided by an extension of the side torso airbag or by a head curtain airbag.
Main Causes of B0020 Error Code
- Damaged or broken wires in the airbag control circuit
- Faulty airbag itself
- Problems with connectors or contacts in the circuit
- Faulty SRS system control module
Possible Causes and Diagnostic Methods
| Possible Cause | How to Check? |
|---|---|
| Damaged wires | Visual inspection for damage or breakage |
| Airbag malfunction | Check circuit resistance with a multimeter |
| Connector problems | Check contacts for corrosion or looseness |
| SRS control module malfunction | Diagnosis with an OBD2 scanner |
Symptoms of B0020 Error Code
- The airbag light on the dashboard is illuminated
- The SRS system fails the self-test when the vehicle is started
- No audible signal when ignition is started
- The airbag does not deploy in an accident
Important! Ignoring this error may result in the airbag failing to deploy in an accident, increasing the risk of injury.
Troubleshooting by Symptoms
| Symptom | Possible Solution |
|---|---|
| Airbag light is on | Check and clean contact points, reset the error code |
| Airbag does not deploy in an accident | Replace the defective airbag |
| Damaged wires | Replace the damaged wire section |
| SRS control module malfunction | Repair or replace the control module |
Step-by-Step Guide to Troubleshooting B0020 Code Using a Scanner
- First, connect the OBD-II scanner to the vehicle’s diagnostic port, usually located under the dashboard near the steering column.
- Next, turn on the ignition without starting the engine so that the scanner can communicate with the vehicle’s onboard computer. Access the fault code section of the scanner to retrieve the stored codes, making sure to record any other fault codes alongside B0020 for a comprehensive view.
- After retrieving the fault codes, perform a visual inspection of the airbag system components, focusing on the wiring harness and connectors. Note any signs of damage or corrosion, which can lead to excessive resistance. After a visual inspection, use the scanner’s real-time data monitoring function to observe the airbag system’s behavior in real time. Check for abnormal voltage and resistance readings, which may indicate high resistance points.
- If the initial troubleshooting is unsuccessful, use a multimeter to perform continuity and voltage drop tests, and compare the readings to the manufacturer’s specifications to identify any discrepancies.
- After the repair is complete, use the scanner to clear the fault codes and perform a system reset. Finally, conduct a test drive to ensure the B0020 code no longer appears, confirming the effectiveness of the repair.
- Any repairs or modifications related to the airbag system must be performed in conjunction with a certified professional to maintain safety and integrity.
Will the B0020 code disappear on its own?
Most fault codes will disappear on their own once the vehicle’s onboard system no longer detects the problem. However, if your vehicle still has this fault code, it should be properly diagnosed to avoid more serious problems.
