U0473: Invalid Data Received From Restraints System Sensor C
What to do
The airbag warning light means the airbags may not deploy correctly in a crash — and where a side sensor is involved, the side airbags and curtains have the least time to react of any on the car.
These sensors often live inside the pillar between the doors, behind the trim, at about the height of the seat belt mounting.
Two things are worth mentioning to a garage. First, any water inside the car — a damp carpet, a wet sill, condensation, a leaking windscreen seal or sunroof drain. Water runs down inside that pillar and collects exactly where the sensor is. Second, any trim that has been off: seat belt work, sill trims, carpets lifted or dried, speakers or amplifiers installed. A connector left unseated after a job that had nothing to do with airbags is a very common cause.
As before: do not have the light cleared, and refuse any offer to fit a resistor in place of a sensor.
What this code means
A restraints system sensor is reporting a value that cannot be accepted as true. See U0471 for the family's framing and U0452 for the safety rules.
Where the sensor in question is a side one — in the B-pillar, the sill or the door — the environment is different enough from a front sensor to change what should be suspected.
A B-pillar sensor sits inside the pillar behind the trim, at the height of the seat belt anchor and just above the sill. That location has three consequences worth knowing:
- It is reached by water running down inside the pillar from a door seal, a roof drain or a leaking windscreen surround, and the sill it sits above is where that water collects.
- It is behind trim that comes off for seat belt work, sill trim replacement, carpet drying and audio installation, so it is disturbed by jobs that have nothing to do with restraints.
- It shares the area with the seat belt pretensioner and the belt height adjuster, and a connector left unseated after work on either produces exactly this.
And the side of the car is where sensing is hardest, for the reason set out at U0453: there is no crumple zone to measure, so the decision has to be made from a much smaller and faster signal. A side sensor reporting implausibly is therefore not a marginal fault — it is the input for the airbags with the least time to work with.
Likely causes
Start here
- Corroded or loose connector · easy
- Water ingress into connector · moderate
- Impact sensor disturbed during body repair · moderate
- Damaged wiring under the front seats · moderate
Less common
- Damaged wiring harness · moderate
- Faulty restraints control module · specialist
Symptoms
Components involved
Information, not instruction
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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.
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