What does an EVAP leak detection pump do?
A key part of the Evaporative Emissions Control System is the evaporative leak detection pump. By pressurizing the fuel system, the evaporative leak detection pump allows the engine computer to detect any leaks which may be permitting gas vapors to escape.
How does an EVAP leak detection switch work?
If the first checks pass, the PCM then uses the LDP to seal the vent valve and pump air into the system to pressurize it. If a leak is present, the PCM will continue pumping the LDP to replace the air that leaks out. The PCM determines the size of the leak based on how fast/long it must pump the LDP as it tries to maintain pressure in the system.
What is the purpose of a leak detection pump?
The main purpose of the LDP is to pressurize the fuel system for leak checking. It closes the EVAP system vent to atmospheric pressure so the system can be pressurized for leak testing. The diaphragm is powered by engine vacuum. It pumps air into the EVAP system to develop a pressure of about 7.5′ H20 (1/4) psi.
How to diagnose EVAP leak detection pump p1494?
NOTE #3: Apart from a repair manual for the application being worked on, a graduated vacuum gauge is required item to diagnose P1494 accurately. Record all fault codes present, as well as all available freeze frame data. This information can be of use should an intermittent fault be diagnosed later on.
What to do if you have a leak in your EVAP system?
If the first checks pass, the PCM then uses the LDP to seal the vent valve and pump air into the system to pressurize it. If a leak is present, the PCM will continue pumping the LDP to replace the air that leaks out.
What problems can occur from an EVAP leak?
Since the EVAP system deals with the management of gas and its fumes it can be dangerous when certain malfunctions occur. One such problem can cause the charcoal canister to fill will raw fuel and start to leak which can cause a fire hazard .
What would cause a leak in the EVAP system?
Here is a complete list of the most common EVAP leak causes: Broken cap or the wrong cap for the vehicle Punctured vapor hose or tube Broken or worn-out O-ring seal Any other leak that altered the flow of emissions You may also get an Evap leak if your vehicle is old or poorly maintained to allow pressure to build up in its systems.
How serious is an EVAP leak?
If the gas cap is on correctly, there may be a more serious issue, such as a leak in the fuel system. If your Check Engine Light comes on and you suspect a leak in your EVAP system, it is best to have a mechanic inspect the vehicle.
How can I fix EVAP small leak?
- Verify that the gas cap is firmly tightened onto the gas tank entry point.
- and lift the front end of the vehicle with a floor jack far enough that you can fit underneath.
- Locate the EVAP service port adapter within the engine’s compartment.