B1304F0 on Seat: Left front seat belt tensioner control module No tensioning due to undervoltage
Diagnostic trouble code B1304F0 on Seat vehicles — what it means, the common
causes, and how to confirm the real fault before replacing parts.
What does B1304F0 mean?
B1304F0 indicates: Left front seat belt tensioner control module No tensioning due to undervoltage.
This relates to the Body system.
Common causes of B1304F0
undervoltage at the left front seat belt tensioner control module J854
loss of terminal 30 or terminal 15 supply voltage to the airbag control unit J234 or J854
interruption in the sub-bus/LIN bus/Extended CAN bus connection between J854 and J234
What to check (live data)
terminal 30 voltage supply status
terminal 15 voltage supply status
LIN bus / Extended CAN bus / sub-bus signal status between J854 and J234
Parts often involved in B1304F0
left front seat belt tensioner control unit J854
airbag control unit J234
data bus diagnostic interface J533
Don't replace parts until the root cause is confirmed — many of these codes are caused by wiring, a connector or an upstream fault, not the part itself.
Get the confirmed root cause for B1304F0 — on YOUR vehicle
A code is a symptom, not a diagnosis. AutoDX Pro cross-checks several
independent assessments, pinpoints the actual root cause, gives you the
exact tests to confirm it, and shows the parts — only after the cause is
confirmed. Reads your scan-tool photo and decodes your VIN with open
recalls.
B1304F0 is a diagnostic trouble code: Left front seat belt tensioner control module No tensioning due to undervoltage.
What are the common causes of B1304F0 on a Seat?
Common causes include: undervoltage at the left front seat belt tensioner control module J854, loss of terminal 30 or terminal 15 supply voltage to the airbag control unit J234 or J854, interruption in the sub-bus/LIN bus/Extended CAN bus connection between J854 and J234. The exact cause depends on the vehicle — confirm it before replacing parts.
Can I keep driving a Seat with B1304F0?
It depends on the fault and your symptoms. Some causes are minor, others can damage components or affect safety. Get the root cause confirmed before deciding.
How do I fix B1304F0 on a Seat?
Confirm the actual root cause with targeted tests first, then replace only the part that's at fault. AutoDX Pro gives you the root cause, the exact tests, and the parts for B1304F0 on your specific Seat.