P05B8
Restraint Deployment Signal Circuit Open
The signal line that the restraint control module uses to inform the engine ECU about a deployment event has an open circuit. The ECU cannot run its post-crash strategy (fuel cutoff, hazard lights, unlock) automatically on impact.
- Check engine light: Yes
- Emissions related: No
- Repair difficulty: medium
Common causes
Ordered by how often each turns out to be the cause.
- Open in signal wireCommon
- Pin pushed back out of connector bodyLess likely
- Cracked solder joint inside the module or sensorLess likely
Parts involved
- Restraint Control Module
- Restraint Signal Wiring
P05B8 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.