P0496: EVAP System High Purge Flow
What Does P0496 Mean?
P0496 is a diagnostic trouble code indicating: EVAP System High Purge Flow. This code relates to the emission controls system. It has been reported in NHTSA complaints across 8 different vehicle models.
The emission control system reduces harmful exhaust pollutants through several subsystems: EGR (Exhaust Gas Recirculation) recirculates a portion of exhaust back into the intake to lower combustion temperatures and reduce NOx. The secondary air injection system pumps fresh air into the exhaust during cold starts to help the catalytic converter light off faster. The catalytic converter converts CO, HC, and NOx into CO2, H2O, and N2. The EVAP system captures fuel vapors from the tank and purges them into the engine for combustion. When any of these systems malfunction, the vehicle will fail emissions testing and the ECM will set a DTC.
Symptoms of P0496
- ⚠️ Check engine light on
- ⚠️ Failed emissions/smog test
- ⚠️ Possible rough idle or stalling (EGR stuck open)
- ⚠️ Fuel smell (EVAP leak)
- ⚠️ Reduced performance in some cases
- ⚠️ Increased tailpipe emissions
Common Causes
- 🔍 Carbon buildup causing EGR valve to stick
- 🔍 EVAP system leak (gas cap, hose, canister, purge valve)
- 🔍 Catalytic converter below efficiency threshold (aging)
- 🔍 Secondary air pump failure or check valve stuck
- 🔍 Wiring or vacuum line issue in emission control circuit
P0496 Reports by Year
Real Owner Reports
From NHTSA complaint database — actual owner descriptions.
"2019 Ford Escape Titanium Eco Boost 2.0 w/ 86,442 miles. Regularly maintained, no accidents, no previous owners. DTC for misfire cylinder #1. Performed coolant pressure test, found system losing pressure and cylinder intrusion, with matching symptoms, recommend further diagnostics. Check engine l"
— Ford Escape owner, 04/26/2024
"When getting gas..afterwards went to start and it would act like it wasn't getting gas..within hours after the check engine light came on..took to dealer to read trouble code..came up as a p0496..evap purge valve sticking open..also have noticed the built in remote start function is not working and "
— Ford Escape owner, 11/23/2023
"PURCHASED VEHICLE IN OCTOBER OF 2019, IN FEBRUARY 2020 HAD ENGINE LIGHT COME ON AND THE CODE P0496 WHICH IS A PURGE VALVE ERROR AND TOOK TO SERVICE AND THEY STATED THAT FORD HAD TO HAVE THIS HAPPEN TWICE, SO ON MARCH 17, 2020, IT HAPPENED AGAIN AND WAS TAKEN TO SERVICE AGAIN AND IT WAS REPLACED. AL"
— Ford Escape owner, 02/27/2021
Source: NHTSA Complaints Database
Most Reported Vehicles for P0496
Based on NHTSA owner complaint data.
| # | Vehicle | Reports |
|---|---|---|
| 1 | CHEVROLET TRAVERSE | |
| 2 | FORD ESCAPE | |
| 3 | VOLKSWAGEN ATLAS | |
| 4 | FORD EXPLORER | |
| 5 | FORD FUSION | |
| 6 | FORD EDGE | |
| 7 | DODGE CHARGER | |
| 8 | GMC TERRAIN |
P0496 Reports by Vehicle
Detailed NHTSA complaint analysis for each vehicle model.
Diagnostic Tips
- For EVAP codes: start with the gas cap — tighten it and clear the code. If it returns, use a smoke machine to find the leak
- For EGR codes: remove and inspect the EGR valve — carbon buildup causing sticking is extremely common and cleanable
- For catalyst codes: check upstream O2 sensor first — a bad sensor can falsely report low catalyst efficiency
- For secondary air codes: listen for the air pump running during cold start — it should run for 30-90 seconds
Common Mistakes to Avoid
- ❌ Replacing the catalytic converter based on a P0420/P0430 code alone — diagnose the root cause first (O2 sensor, exhaust leak, engine running rich)
- ❌ Ignoring a loose gas cap as the cause of EVAP codes — this is literally the #1 cause and the cheapest fix
- ❌ Using aftermarket catalytic converters in states with strict emissions laws (California) — CARB-compliant converters are required
Frequently Asked Questions
Will I pass emissions with a check engine light on?
Can I just clear the code before emissions testing?
How much does a catalytic converter cost?
What To Do Next
Possible Fixes
- 🔧 Clean or replace EGR valve
- 🔧 Replace gas cap (EVAP codes)
- 🔧 Replace EVAP purge or vent solenoid
- 🔧 Replace catalytic converter
- 🔧 Replace secondary air pump or check valve
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Find your vehicle above
Click your make and model for real owner reports and common causes specific to your vehicle.
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Check for recalls
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Get a professional diagnosis
A code alone doesn't identify the exact failed part. A diagnostic ($50–$150) pinpoints the root cause.