B0071: First Row Centre Seat Belt Pretensioner Deployment Control
What to do
Get this looked at promptly, and do not attempt it yourself. An airbag fault usually means the whole restraint system has switched itself off, so the airbags and pretensioners may not fire in a crash — the car drives normally and is far less able to protect you. Never probe airbag wiring with a multimeter: the current an ordinary meter uses can set off the charge. This needs a workshop with the right equipment and the correct disable procedure.
What this code means
The deployment loop for the first row centre seat belt pretensioner is faulty.
A modern seat belt is an active device, and this is the part of the restraint system people are most surprised to find has explosives in it.
The belt does three things in a crash, in sequence. It locks. A pretensioner fires, pulling several centimetres of slack out of the webbing in a few milliseconds — removing the gap between belt and body so the occupant begins decelerating with the car rather than after it. Then a load limiter lets webbing back out, deliberately, at a controlled force.
That last step is the counter-intuitive one. A belt that simply held firm would stop the chest against a band of webbing hard enough to break ribs — and in a severe crash the belt itself becomes the injury. So the load limiter allows the occupant to move forward a little, spreading the deceleration over a longer distance and capping the force the chest ever sees. It works with the airbag: the belt lets you travel far enough to meet the bag, and the bag catches what the belt let go.
Which is why belts and airbags are tuned as one system and why a fault in either compromises both. A pretensioner that does not fire leaves slack the airbag was not expecting; a load limiter that does not release leaves the chest taking a load the design never intended.
Likely causes
Start here
- Corroded or loose connector · specialist
- Damaged wiring under the front seats · specialist
- Faulty seat belt pretensioner · specialist
- Open circuit in the airbag deployment loop · specialist
Less common
- Restraint device already deployed and not replaced · specialist
Symptoms
Components involved
Information, not instruction
CarGeek is a reference, not a service manual. Its pages are written from public sources and from what other people have found, never from a manufacturer's own service information, so they can be wrong or incomplete for your particular vehicle. Some of what they describe carries real risk: high voltage, fuel under pressure, stored energy, hot and moving parts.
Have anything you intend to act on checked by a trained person against the manufacturer's own procedure for your vehicle. Nothing here replaces that procedure.
Community experience
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