With clean air and reduced pollution in mind, vehicle manufacturing companies have developed systems designed to minimize harmful emissions. Of such systems is the Evaporative Emission Control, or EVAP, system.
This guide will provide an overview of the EVAP system, its components, common issues like EVAP emission control system leaks, and answers to frequently asked questions.
What is an EVAP System?
The EVAP system is a crucial part of a vehicle’s emissions control strategy. Its primary function is to prevent fuel vapors from escaping into the atmosphere. These vapors contain hydrocarbons, which contribute to smog formation and air pollution. The system captures these vapors, stores them temporarily, and directs them to the engine for combustion.
How the EVAP System Works
When the engine is on, the purge valve opens up the fuel vapors of the charcoal canister into the engine intake manifold. Inside the engine, it burns these vapors along with a mix of fuel and air. This results in less harmful emissions. Even better, the system self-tests for leaks to ensure that the system remains intact.
Common EVAP System Problems
One of the most common issues with the EVAP system is an EVAP emission control system leak. This occurs when the system’s airtight integrity is compromised. Such leaks can result from:
- Damaged hoses or seals
- Cracked charcoal canister
- Malfunctioning purge or vent valves
An evap emission system leak detected error is often indicated by the Check Engine Light (CEL) on your dashboard. This warning signals the need for a diagnostic scan to identify the root cause of the issue.
EVAP System Problems Symptoms
- Check Engine Light: The CEL usually illuminates when the system detects a problem.
- Oil: A smell of oil around the vehicle may indicate exhaust fumes.
- Improper Fuel Use: Running water can cause harmful fuel vapors.
- Vehicle Starting Problems: In rare cases, a faulty EVAP system will affect the fuel-air mixture and cause starting problems.
Diagnosing EVAP System Problems
If your vehicle’s onboard diagnostics system flags an evap emission system leak, a mechanic will typically:
- Use a diagnostic scan tool to retrieve trouble codes.
- Perform a visual inspection of the system components.
- Conduct a smoke test to identify leaks in the system.
Fixing EVAP System Issues
This again will depend on the type of problem because some problems are inexpensive, such as replacing damaged hoses or seals, but the cost is higher if one has to replace a cracked charcoal canister or faulty valves. Proper attention will prevent further damage and ensure the vehicle does not violate emission regulations.
Preventing EVAP System Problems
- Regular Maintenance: Inspect the EVAP system components during routine vehicle maintenance.
- Avoid Overfilling the Fuel Tank: Overfilling can damage the charcoal canister.
- Use Quality Fuel Caps: A damaged or missing fuel cap is a common source of evap emission control system leaks.
Your vehicle’s EVAP system is essential for emissions control, catching dangerous fuel vapors and processing them. Knowing how the system works, issues with it, such as evap emission system leaks, and how to cope with those problems can go a long way in keeping your vehicle’s performance and environmental compliance in check.
In Philadelphia, Autoworx is a trusted auto repair shop for diagnosing and repairing evaporative emission system problems. Their certified technicians are equipped with advanced diagnostic equipment to quickly find problems like evap emission control system leaks or faulty components.
FAQs About the EVAP System
How do you fix EVAP emissions?
You have to identify the problem and repair it. You have to replace faulty parts like hoses, seals, purge valves, or even the charcoal canister. There are diagnostic scans and smoke tests that can detect where the problem is located.
What happens when the EVAP system goes bad?
The fuel vapors leak out into the atmosphere, which creates air pollution. The vehicle may lose some of its fuel efficiency, and there is a good chance the Check Engine Light will turn on, which could result in the vehicle failing its emissions tests.
What happens when the EVAP system goes bad?
Cost of repairing the EVAP system depends on the specific issue. Minor problems like a faulty fuel cap or damaged hose can be inexpensive to fix, usually costing under $100. However, more significant repairs, such as replacing the charcoal canister, can range from $200 to $600 or more, depending on the vehicle make and model.
Can I drive with an EVAP system leak?
While an EVAP system leak won’t likely cause immediate performance issues, it’s not a good idea to ignore it either. Driving with a leak can lead to increased emissions and potential fuel wastage in addition to failure of the emissions inspections.
How would I know if my vehicle's EVAP system were working?
A good, healthy indicator is if a Check Engine Light never illuminated and the vehicle performed normally during its service life. Much more definitive, however, are regular vehicle diagnostics and vehicle inspections.