U0479: Invalid Data Received From Restraints System Sensor I
What to do
The airbag warning light means the crash protection may not be working properly.
A car with nine crash sensors is a well-equipped one — side and curtain airbags, knee airbags, rear pretensioners, pedestrian protection, perhaps a rollover system. Every one of those needs its own sensor, which is how the count gets this high.
One question is worth asking before any part is bought: does your car actually have that sensor? Cars are built on the same body in different specifications, and the airbag computer has to be told which equipment yours has. If that computer has ever been replaced — particularly with a second-hand one, or after accident repair — it may be looking for a sensor your car never had. No amount of testing finds a fault, because there is nothing there to fail. Correcting the coding is the fix, and it is far cheaper than the search.
If the sensor does exist, everything on the other pages in this family applies: mention any bumper, door, seat or trim work, and any tow bar or accessory fitted.
Do not have the light cleared, and refuse 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.
A ninth restraints sensor puts the vehicle in a small category — a large or heavily specified car with side, curtain, knee, centre and rear airbags, rear pretensioners, pedestrian protection and often a rollover system as well. Each of those needs its own input, and that is how the count reaches this far.
Which makes the first question the one from U0446: is the sensor fitted at all? Restraints configuration varies by market and specification on a shared body — a car built without curtain airbags, without the pedestrian system, or without rear pretensioners still has a restraints module that must be told which of them exist. A module coded for a higher specification than the car was built to looks for a sensor that was never installed and reports exactly this, and there is nothing to find because there is nothing there.
That is a coding correction rather than a repair, and it follows the usual causes: a replacement module coded from a generic file, a used module from a better-equipped car, or a restraints module programmed from the wrong build data after an accident repair.
Where the sensor does exist, everything in this family applies unchanged — the repair history, the mounting, the connectors, and the intermittent behaviour at U0478.
One numbering note. The standard continues this family past I into the letter-suffixed part of the U047x range, so a scan tool naming a restraints sensor beyond I is reporting something outside the numbering this corpus enumerates. The reasoning on this page still applies to it.
Likely causes
Start here
- Module not coded to the vehicle · specialist
- Second hand module locked to another vehicle · specialist
- Corroded or loose connector · easy
- Impact sensor disturbed during body repair · moderate
Less common
- Damaged wiring harness · moderate
- Faulty restraints control module · 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
Be the first to write this up
Nothing posted about this yet. Whatever you found is worth writing down — even a dead end saves someone the same afternoon.
What makes one worth reading:
- The car — make, model, year and engine. The same fault behaves differently on each.
- What you measured, not only what you replaced.
- What actually fixed it — or that nothing did, which is worth knowing too.
Sign in or create an account to add what you found about U0479.