Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P05BB Restraints Deployed

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modePossible

After a crash the restraint control module tells the engine module that airbags or belt tensioners have fired; the engine module then cuts the fuel pump (Ford: until the ignition is cycled) and possibly the engine. Depending on the maker the message travels over CAN and/or a dedicated wire with a defined level or voltage drop. P05BB is an event code: the engine module received a valid deployment message. The fuel pump is cut, the engine may stop, doors are unlocked by other modules, and Ford's engine module freezes recorded data. After a crash the restraint module must be replaced; a used module with a stored crash can also cause it. No manufacturer document available to us uses this code; it is a safety function, not an emission-relevant monitor, so usually without warning lamp.

Likely causes

Real accident with airbag or belt tensioner deployment
Deployment after a hard underbody hit (e.g. off-road)
False message from wiring or module fault
Used restraint module with stored crash fitted

Symptoms

  • Engine stops or will not start (fuel cut-off)
  • Airbag warning light
  • Doors unlocked, fuel cut-off message

Repair estimate

DifficultyHardWorkshop job
Parts and labour€500–3,000
Time2–8 h

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

Parts involved

restraint control modulecrash signal wiringengine control module

Related codes

P05B8P05B9P05BAP0230U0151

References: static.nhtsa.gov, patents.google.com, law.cornell.edu.