Fault Family System: Powertrain (P-Codes) 4 SAE Codes

Restraint Deployment Signal Circuit

Diagnostic & Technical Explanation

Code P05B8 (Restraint Deployment Signal Circuit/Open) sets when the ECM's restraint-deployment input circuit from the airbag control module reports an open, shorted, or active-deployment condition, used to trigger fuel shutoff and hazard-lamp activation after a crash. Causes are a corroded connector in the interface harness, chafed wiring between the airbag module and ECM, or an actual prior deployment event that has not been serviced/reset.

These 4 diagnostic trouble codes share one detection mechanism and one repair path, which is why MechanicDB groups them into a single authored fault family rather than repeating the same explanation 4 times.

Codes in this family (4)

Code	Definition	Repair coverage
P05B8	Restraint Deployment Signal Circuit/Open	3 ranked fixes
P05B9	Restraint Deployment Signal Circuit Low	3 ranked fixes
P05BA	Restraint Deployment Signal Circuit High	3 ranked fixes
P05BB	Restraints Deployed	3 ranked fixes

What this page does not show

This page publishes the fault mechanism and the code index. The licensed dataset adds, for every one of the 15,886 codes, the full authored repair set (56,729 procedures in total) with the fields deliberately withheld here:

Procedures 2..n after the first-listed procedure
Aftermarket parts cost ranges in USD (est_parts_cost_min/max_usd)
Professional labor-hour estimates (est_labor_hours)
Step-by-step diagnostic and repair instructions
Replacement-part mappings and catalog lookups
6,637 manufacturer-specific OEM codes across 32 makes ($149 tier)

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