Code B0039 indicates a fault in the deployment control circuit for the second-row right frontal airbag (Stage 1). The restraints control module has detected an open, short, or resistance value outside the expected range in the squib circuit or its wiring.
A broken wire, corroded connector, or damaged clock-spring/coil in the second-row right frontal airbag deployment loop prevents the control module from measuring the correct squib resistance.
Insulation damage or a pinched harness creates a low-resistance path to ground or battery voltage, triggering the fault.
The inflator squib itself measures out of specification, typically due to internal element degradation or manufacturing defect.
Oxidation, bent terminals, or incomplete seating at the airbag connector or the restraints control module connector adds resistance or creates an intermittent open.
The module's deployment driver or monitoring circuitry for this loop has failed; this is rare and should be considered only after wiring and inflator are verified.
No. The restraints control module continuously monitors loop resistance; the code will return immediately after clearing if the underlying fault remains.
RCM failure is uncommon. The vast majority of B0039 cases are caused by wiring, connector, or inflator issues. Replace the RCM only after the deployment loop and harness are verified good.
Yes. When B0039 is active, the control module disables the second-row right frontal airbag to prevent inadvertent deployment, so that airbag will not fire in a collision.
A digital multimeter and a scan tool capable of reading SRS data are required. Some manufacturers specify a dedicated SRS load tool or breakout box to safely simulate the inflator during circuit testing.