System: Powertrain (P-Code)
SAE Standard (Generic)
Family: Crankcase Ventilation Hose Disconnected
Code P2C91: Crankcase Ventilation System - Hose B Disconnected
Diagnostic & Technical Explanation
Code P2C91 (Crankcase Ventilation System - Hose B Disconnected) sets when the ECM's crankcase pressure model detects a pressure signature consistent with a specific PCV hose (A or B) being disconnected or split, rather than a generic system leak. A hose that popped off a fitting from age-hardened rubber, a split hose from oil-vapor degradation, or a loose clamp are the common causes.
First-listed procedure
Rank #1
Inspect and reseat the named PCV hose
Easy DIY
This is the first procedure in the authored
consideration order, not a measured cause likelihood. Execute it only when its prerequisites
and diagnostic findings support it. Its cost and labor estimates (where known), the step-by-step procedure and the
remaining 2 procedure(s) are in the licensed dataset. Ordering context.
Full family: Crankcase Ventilation Hose Disconnected
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)