Cause
Impact sensor disturbed during body repair
A crash sensor was removed, refitted or replaced during panel work, and something about how it went back is wrong.
This is the leading cause of restraints faults on any vehicle that has ever been repaired, and the reason is simply where the sensors live. They bolt to the bumper beam, the front rails, the B-pillars, the sills and the door structures — the exact parts removed for a bumper change, a headlight, a radiator, a door skin or a wing. None of that work is about airbags, so the sensors get treated as fasteners to undo rather than as calibrated instruments.
Four specific things go wrong, and each defeats a static test.
- Orientation. A sensor measures acceleration along a defined axis. Fitted rotated or reversed, it reads a genuine impact wrongly while measuring perfectly.
- Mounting. It reports the motion of what it is bolted to, so an under-tightened bolt, a washer that does not belong, or paint, underseal or corrosion between it and the panel damps and delays what it sees.
- Part number. A sensor that fits and plugs in may be calibrated for a different structure or model year.
- The harness. Trapped, stretched, or routed against an edge that will chafe through in a year.
So the question that finds this is narrow rather than general. "Has it been in an accident?" gets an honest and unhelpful no. "Has the bumper ever been off? Has a wing, headlight or door been replaced?" finds it — and on a second-hand vehicle the owner frequently does not know, which is why the inspection matters more than the interview.
And the failure mode this produces is the worst kind: everything passes on the bench, and the system misjudges a real crash.
Typically a moderate job.
Codes this can cause (25)
Codes where this is a likely explanation first, rather than merely a possible one.
- U0152 Lost Communication With Side Restraints Control Module — Left Likely for this code High
- U0153 Lost Communication With Side Restraints Control Module — Right Likely for this code High
- U0170 Lost Communication With Restraints System Sensor A Likely for this code High
- U0171 Lost Communication With Restraints System Sensor B Likely for this code High
- U0172 Lost Communication With Restraints System Sensor C Likely for this code High
- U0173 Lost Communication With Restraints System Sensor D Likely for this code High
- U0174 Lost Communication With Restraints System Sensor E Likely for this code High
- U0175 Lost Communication With Restraints System Sensor F Likely for this code High
- U0178 Lost Communication With Restraints System Sensor I Likely for this code High
- U0179 Lost Communication With Restraints System Sensor J Likely for this code High
- U0452 Invalid Data Received From Restraints Control Module Likely for this code High
- U0453 Invalid Data Received From Side Restraints Control Module — Left Likely for this code High
- U0454 Invalid Data Received From Side Restraints Control Module — Right Likely for this code High
- U0471 Invalid Data Received From Restraints System Sensor A Likely for this code High
- U0472 Invalid Data Received From Restraints System Sensor B Likely for this code High
- U0473 Invalid Data Received From Restraints System Sensor C Likely for this code High
- U0474 Invalid Data Received From Restraints System Sensor D Likely for this code High
- U0475 Invalid Data Received From Restraints System Sensor E Likely for this code High
- U0476 Invalid Data Received From Restraints System Sensor F Likely for this code High
- U0477 Invalid Data Received From Restraints System Sensor G Likely for this code High
- U0479 Invalid Data Received From Restraints System Sensor I Likely for this code High
- U0176 Lost Communication With Restraints System Sensor G High
- U0177 Lost Communication With Restraints System Sensor H High
- U0478 Invalid Data Received From Restraints System Sensor H High
- U0480 Invalid Data Received From Seat Belt Pretensioner Module B High
Information, not instruction
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