Fault Family System: Powertrain (P-Codes) 2 SAE Codes

Crankcase Ventilation Hose Disconnected

Diagnostic & Technical Explanation

Code P2C90 (Crankcase Ventilation System - Hose A 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.

These 2 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 2 times.

Codes in this family (2)

Code	Definition	Repair coverage
P2C90	Crankcase Ventilation System - Hose A Disconnected	3 ranked fixes
P2C91	Crankcase Ventilation System - Hose B Disconnected	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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