What is a leak detection pump?
A leak detection pump is a critical part of your car’s evaporative emission control (EVAP) system. Its primary job is to monitor the EVAP system and detect fuel vapor leaks.
The EVAP system prevents your vehicle from releasing excessive pollutants by collecting the fuel vapors that build inside your fuel tank. The vapors collect in a charcoal canister, where they’re converted into hydrocarbons and carbon dioxide.
The hydrocarbons are recycled through the purge valve back into the intake manifold. From there, they mix with air and fuel and burn up as part of the combustion process. The carbon dioxide exits the canister through the vent valve and is released into the outside air.
The leak detection pump is designed to catch EVAP system leaks. When the pump detects a large or small leak, it triggers the car’s onboard diagnostic (OBD) system, which illuminates the check engine light.
When should I replace the leak detection pump on my car?
There is no set replacement schedule for the leak detection pump. That means you only need to replace it when it fails. Here are the most common signs of a bad leak detection pump:
Check engine light: Most of the time, the only sign of a bad leak detection pump is a check engine light. But since the light may appear for many reasons, you’ll have to use an OBD scan tool to identify the diagnostic trouble code (DTC).
Fuel smell: An EVAP leak will most likely result in a strong gas odor. While this can indicate general EVAP system problems, it can also be a sign of a faulty leak detection pump.
Performance problems: A failed leak detection pump can disrupt the EVAP system, resulting in performance issues. You may experience a rough idle, reduced fuel economy, or issues accelerating.
Failed emissions test: If your leak detection pump is bad, you will likely be unable to pass an emissions test. Depending on where you live, this can have legal consequences.
Keep in mind: These issues can indicate other EVAP or fuel system problems, like a faulty gas cap, bad fuel pump, or malfunctioning EVAP canister. To accurately diagnose your issue, you should visit a certified mechanic.
How often should I replace my leak detection pump?
The leak detection pump isn’t a part that typically requires regular maintenance, so there are no set replacement intervals for it. You’ll only need to replace the pump if it fails or malfunctions.
The most common sign of a faulty leak detection pump is a check engine light, but you may also experience a fuel odor or a failed emissions test.
Can I replace my leak detection pump myself?
A leak detection pump replacement can make a solid DIY project. It’s a mid-level repair job that requires basic mechanical knowledge and access to basic tools.
For experienced home mechanics, the job should be simple and straightforward. But if you’re a car repair novice or uncomfortable working with the EVAP system, you should contact a professional mechanic.