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

P05BA Restraint Deployment Signal Circuit High

Check engine lightUsually off
EmissionsNot relevant
Drive cycleNot required
Limp modeNo

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. P05BA means the signal line stays above its valid range – a short to battery or ignition voltage, or with a pull-up in the engine module an open circuit. The fuel cut-off may then not work via this line. 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

Signal wire shorted to battery or ignition voltage
Open circuit with pull-up in the engine module
Retrofitted loads or harness damage after accident repair
Restraint or engine module

Symptoms

  • Code stored
  • Vehicle drives normally
  • No check engine light

Repair estimate

DifficultyMediumWorkshop job
Parts and labour€80–300
Time0.5–2 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

P05B8P05B9P05BBU0151

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