Serious — S4Audi A4 · european tier
B0020 on Audi A4
The B0020 diagnostic trouble code on a Audi A4 indicates left side airbag deployment control. For Audi 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 Audi A4
Common on This Vehicle?
The B0020 code is relatively common on Audi vehicles and often appears alongside other diagnostic codes.
Repair Costs for B0020 on Audi A4
These repairs are commonly needed to resolve the B0020 code on a Audi A4:
See all repair costs for Audi A4 →Symptoms on Audi A4
- •Airbag/SRS warning light on — airbags may be disabled
- •Check Engine Light illuminated
- •Seat belt pretensioner may not deploy in a collision
- •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