Faulty connector or poor contact at the passenger airbag connector or under-dash SRS connectors; Damaged or chafed wiring in the passenger airbag circuit (open circuit, short to ground or short to voltage); Passenger frontal airbag module or its stage 3 initiator out of specification or faulty; Connector or wiring disturbed by recent work on the dashboard, glovebox, seat or carpets; Low or unstable supply voltage to the SRS control unit from a weak battery or poor earth; Faulty SRS control unit or its internal deployment driver; Water or corrosion in the SRS wiring or connectors, for example from a leak or flood damage.

B0012

Passenger Frontal Stage 3 Deployment Control.

Generic
Body
Generic code
High severity

How this code is built

B: SystemBody
0: Defined bySAE, the same on every car
0: AreaBody area 0
12: FaultThe specific fault in that area

What it means

B0012 is the generic code for a fault in the passenger frontal stage 3 deployment control circuit. The SRS control unit runs self-tests on the airbag firing circuits and saw a reading outside its expected range, such as an open circuit, a short to ground or voltage, or abnormal resistance. How many stages the car has and which airbag parts sit on this circuit depends on the model, so check the manufacturer wiring information.

Symptoms

Airbag warning light on the dashboard, either lit constantly or flashing
Passenger airbag may not deploy in a crash while the fault is present
Passenger airbag off indicator may behave oddly or the light may stay on
Fault may come and go with seat movement or bumpy roads if a connector is loose
Other SRS codes stored at the same time

Possible causes

Faulty connector or poor contact at the passenger airbag connector or under-dash SRS connectorslikely
Damaged or chafed wiring in the passenger airbag circuit (open circuit, short to ground or short to voltage)likely
Passenger frontal airbag module or its stage 3 initiator out of specification or faultypossible
Connector or wiring disturbed by recent work on the dashboard, glovebox, seat or carpetspossible
Low or unstable supply voltage to the SRS control unit from a weak battery or poor earthpossible
Faulty SRS control unit or its internal deployment driverrare
Water or corrosion in the SRS wiring or connectors, for example from a leak or flood damagerare

How to diagnose

Read all stored and pending SRS codes and save the freeze frame data. Note whether B0012 is current, intermittent or history, and whether related codes are present.
Check the battery and charging voltage, and note any recent dashboard, seat or electrical work or crash history.
Follow the manufacturer's safe procedure before touching any airbag part: switch off the ignition, disconnect the battery and wait the specified time for the SRS capacitors to discharge.
Visually inspect the passenger airbag connector, the under-dash SRS connectors and the harness for damage, corrosion, bent pins, pinched wiring and loose or unlatched locks.
Check that any connector shorting clips or locking devices are fully seated and undamaged, as the manufacturer's wiring information describes.
Do not measure airbag modules or initiators with an ordinary meter or a test light. Use only the manufacturer's approved test method to check circuit resistance and for shorts, working from the harness side.
Carry out a wiggle test on the harness with the system safely reconnected, then clear the codes and see whether B0012 returns.
If the wiring is good, use the manufacturer's procedure to decide between a faulty airbag module and a faulty SRS control unit.

How to fix

Repair or replace damaged connectors and terminals, and secure them correctly.
Repair or replace the damaged section of airbag wiring using the manufacturer's approved method.
Replace the passenger frontal airbag module if it is confirmed faulty.
Correct battery, supply or earth faults that affect the SRS control unit.
Replace or reprogram the SRS control unit only after the circuit and module are proven good and the manufacturer's procedure calls for it.
Clear the codes and confirm the airbag warning light stays off after a full system check.

Can I keep driving?

High severity

The car will usually still drive, but the passenger frontal airbag may not work properly in a crash, so it is a safety risk. Get it inspected and repaired promptly, and avoid carrying a front passenger, especially a child, until it is fixed.

Guide written by AI from the code's definition. Confirm with a diagnosis before replacing parts.