B0033 indicates the supplemental restraint system (SRS) has detected an electrical fault in the third-stage deployment circuit for the second-row left frontal airbag. The code means the airbag control module cannot verify correct resistance or integrity in that specific squib loop, so it disables that deployment path and illuminates the airbag warning light.
The deployment element itself can develop an open circuit, short, or resistance outside the specified range, which is the most common reason the SRS module sets this code.
Damage, pin push-out, corrosion, or chafing in the harness between the SRS module and the second-row left airbag can create high resistance, an open, or a short to ground or power.
Connector half-engagement, moisture intrusion, or terminal fretting can interrupt the precise low-resistance path the deployment circuit requires.
A replacement airbag or harness with different electrical characteristics can place the stage 3 loop outside the calibrated range.
This is uncommon; the module’s internal deployment driver or sensing circuit can fail, but it should only be considered after the airbag and wiring have been verified.
The vehicle will drive normally, but the second-row left frontal stage 3 airbag may not deploy in a collision, so the SRS system is compromised and should be diagnosed promptly.
Usually no. Most B0033 faults are caused by the airbag squib or the wiring/connectors in its loop; the control module itself is a less common cause and should only be considered after those are ruled out.
No. This code refers to the second-row left frontal stage 3 circuit, not a steering-wheel airbag circuit, so the clockspring is not part of this deployment loop.
Not reliably. Airbag codes often require a scan tool capable of communicating with the SRS module and performing its self-test and configuration functions.