Fault Family System: Powertrain (P-Codes) 6 SAE Codes

EVAP Vent Solenoid Circuit

Diagnostic & Technical Explanation

Code P0446 (EVAP System Vent Control Circuit) sets when the ECM detects an open, shorted, or out-of-range condition while driving the EVAP canister vent solenoid, the normally-open valve that must seal the system to atmosphere during a leak test. Causes are a failed solenoid coil, a corroded or unseated connector, debris/ice jamming the valve, or damaged wiring between the ECM and the solenoid.

These 6 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 6 times.

Codes in this family (6)

Code	Definition	Repair coverage
P0446	EVAP System Vent Control Circuit	4 ranked fixes
P0447	EVAP System Vent Control Circuit Open	4 ranked fixes
P0448	EVAP System Vent Control Circuit Shorted	4 ranked fixes
P0449	EVAP System Vent Valve Control Circuit/Open	4 ranked fixes
P0498	EVAP System Vent Valve Control Circuit Low	4 ranked fixes
P0499	EVAP System Vent Valve Control Circuit High	4 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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