B0020: Left Side Airbag Deployment Control

Often crash data

What B0020 means

Side protection on most modern cars comes from a seat-mounted side airbag, a roof-rail curtain, or both. B0020 is the deployment control code for the left side, which is the driver side. When it sets, the module is reporting an event or a fault on that side loop.

After a side impact where the left airbag deployed, B0020 is the stored deployment record. It keeps the SRS light on and locks the module. Like other deployment codes, it can also appear without a crash if the circuit goes open, for example a connector that worked loose under the seat. That is why the car's history matters as much as the code itself.

Common causes

• Left side airbag or curtain deployment in a side impact, leaving stored crash data
• An open circuit from a disconnected or corroded connector, often under the driver seat
• A spent side airbag still plugged in before the new one is installed
• Damaged side-loop wiring after a door or seat is removed for repair

Crash data or hardware fault?

B0020 genuinely goes both ways. If the left side airbag deployed, it is stored crash data our reset clears. If nothing deployed and the code stands alone, it usually means an open or shorted side loop that has to be repaired. A reset on a live circuit fault only buys a few seconds, because the next start-up self-test sets the code right back. We read the resistance and the full code set before we tell you which it is.

Does our reset clear it?

Yes, when B0020 is stored crash data from a deployment. Our airbag module reset clears it and the module reads factory-ready. If it is a live circuit fault, repair the loop first, and we will be upfront about that.

Which makes throw it

B0020 is a generic body code seen across GM, Ford, Nissan, and most makes with side airbags. The left side deployment meaning holds, though a few makes split the front and rear side loops into separate codes.

What to do next

Replace any deployed side airbag and confirm the side loop is intact, then mail us the module. We clear stored crash data and return it ready to install. Related codes: B0010 (passenger frontal), B0051 (deployment commanded), and B1620 (module internal fault).