Serious — S4Mercedes-Benz C-Class · european tier
B0012 on Mercedes-Benz C-Class
The B0012 diagnostic trouble code on a Mercedes-Benz C-Class indicates passenger frontal stage 3 deployment control. For Mercedes-Benz vehicles, this code is commonly triggered by faulty airbag module — most common cause, test before replacing or damaged or corroded wiring/connector in the airbag/srs (supplemental restraint) system circuit.
Can You Still Drive?
Drive to a shop soon. Risk of damage if ignored.
Estimated Repair Cost
$100 – $2,000
for Mercedes-Benz C-Class
Common on This Vehicle?
The B0012 code is relatively common on Mercedes-Benz vehicles and often appears alongside other diagnostic codes.
Symptoms on Mercedes-Benz C-Class
- •Seat belt pretensioner may not deploy in a collision
- •Check Engine Light illuminated
- •Airbag/SRS warning light on — airbags may be disabled
- •Diagnostic trouble code (DTC) stored in module memory
Common Causes
- •Faulty airbag module — most common cause, test before replacing
- •Damaged or corroded wiring/connector in the airbag/SRS (supplemental restraint) system circuit
- •Blown fuse or faulty relay for the airbag/SRS (supplemental restraint) system
- •Poor ground connection — check and clean all related ground points
- •Control module fault — rare but possible, only consider after ruling out simpler causes