Network, generic

U0551 Invalid Data Received From Impact Classification System Module

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

An impact classification system module helps the restraint system judge what kind of collision is under way, for example frontal, side or angled, and how severe it is, so that the right airbags and pretensioners fire at the right stage. U0551 means another module, typically the airbag or restraint controller, receives messages from this unit whose content fails its plausibility or integrity checks. No manufacturer has published a description or setting criteria for this code. Patents on bus-connected crash sensing such as US7832762 show why such traffic is protected: deployment decisions travel over the network to the protection devices. With the classification input in doubt, the airbag warning lamp comes on and the system cannot rely on that information. Treat it as a safety fault; a silent module gives U0250.

Likely causes

Internal fault in the impact classification module
Module or restraint controller not configured/programmed after replacement or crash repair
Damaged wiring or connector after collision or interior work

Symptoms

  • Airbag/SRS warning lamp on
  • Restraint system message in the instrument cluster
  • Passenger airbag status indicator behaving abnormally

Repair estimate

DifficultyShop_onlyWorkshop job
Parts and labour€100–900
Time0.5–3 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

impact classification module

Related codes

U0250U0452U0151

References: en.wikipedia.org, patents.google.com.