MODERATE System: EVAP Emissions System SAE J2012 Standard

P0496: Evaporative Emission System Flow During Non-Purge Condition

The ECM detects fuel vapor flow through the EVAP purge line when the purge valve is commanded 0% (closed). The purge solenoid is mechanically stuck open, allowing engine manifold vacuum to draw raw fuel vapor continuously.

Driveability & Safety Advisory

Drivable, but engine will experience extended crank (hard start) immediately after refueling at gas station.

Official Manufacturer TSB Advisories

GM PIP4673 Target: 2010–2017 Chevrolet Equinox / GMC Terrain (2.4L / 3.6L)

Factory Condition: Purge solenoid plunger sticks open with charcoal debris, causing hard start after refueling and P0496.

OEM Service Remedy: Replace intake manifold EVAP purge solenoid valve (Part #12610560).

Physical Component Location & Service Access

Purge solenoid is mounted on the top or side of the engine intake manifold.

Electrical Specifications & Live PID Benchmarks

Scan Tool Live Data Targets

Purge Commanded Duty Cycle: 0% commanded, yet fuel trims show negative (rich)

Digital Multimeter (DMM) Specs

Purge Valve Coil Resistance: 19 – 32 Ohms at 68°F

Documented Model-Specific Case Studies

2013–2018 Ford Escape EcoBoost

Root Cause: Stuck purge valve.

Verified Fix: Replace purge valve assembly.

Technician Inspection & Testing Workflow

1

Unplug electrical connector and vacuum hose from purge valve with engine idling.

2

Place finger over purge valve intake port. If there is vacuum suction while unpowered, the valve is stuck open and defective.

3

Replace purge valve.

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Cost Breakdown

DIY Replacement Parts: $25 – $60
Independent Repair Shop (Parts + Labor): $140 – $260
Standard Diagnostic Time: 1.0 – 2.0 Flat-Rate Hours

Tools & Parts Matrix

Recommended Parts: EVAP purge solenoid valve
Required Test Tools: Pliers, Screwdriver, Scan tool

Diagnostic Questions & Answers

Why does my car only struggle to start after I put gas in it?

A stuck-open purge valve floods the engine intake manifold with heavy fuel vapors while you are pumping gas, creating an flooded engine condition.