A newer key in an older ignition may be enough to trigger the “on” circuit and keep the vehicle running. ![]() Try starting it with a different key if you happen to have one. There are a few things you can do to tell if this is the issue with your car. This is a condition that happens when the ignition lock has worn out.īasically, the vehicle is only being told to “be on” when the starter is engaged, and all systems are going off when releasing the key. When you start your Passat, it may be that the vehicle’s systems are only coming on when you hit the starter. If you do end up cleaning it, make sure that you get a cleaner specifically designed to clean the sensor and nothing else. Here’s a in depth article on how to diagnose a bad mass airflow sensor. Follow the wiring as far as you can and make sure that it is not burnt, frayed, or in any other way damaged. Take a look at the wiring harness around it and make sure that it is plugged in good and tight. If it is not properly giving a proper reading, it is known to make the car not start. It is one of the most important components that the vehicle uses to determine the air/fuel mixture. It sits in between the air filter and the throttle body. The mass airflow or “MAF” sensor meters the amount of air entering your Passat’s engine. If you have a coil on distributor engine, a bad coil can start a car, but might not have enough spark to keep it running. Most modern vehicles are powered by individual coil packs. If it drops lower, the engine dies, but then the fuel pressure bounces back, it’s most likely a bad fuel pump or fuel filter.Īn experienced mechanic with a good scanner can check the voltage at the fuel pump relay to determine if it is getting constant voltage. Now start the engine.ĭoes the fuel pressure drop almost immediately? Does it go all the way to zero? If it drops all the way to 0 and doesn’t come back, it’s most likely the fuel pump relay. Take note of the fuel pressure as you turn the key to the on position. But, most engine’s have a port that will allow you to check the fuel pressure with a gauge that you can rent or buy from a store such as Autozone. The fuel pump may be providing enough fuel pressure when starting the engine, but not providing enough to keep it running. There are a few reasons that you may not have enough fuel pressure. When they don’t have the proper pressure, they can’t run properly. Modern fuel injected engines need a lot of fuel pressure to keep running. Here are some of the most common reasons that your Passat starts then stops running: We recommend looking to see if there are any OBD2 codes before proceeding with any manual diagnosis. Modern vehicles have complex computer systems that can tell you the reason that the vehicle is dying immediately after starting it. This is one of the most common reasons why a car starts and then dies. If there is not enough fuel pressure to meet the needs of the vehicle, the engine will shut down. As soon as the engine gets enough fuel, air, and spark it runs on its own.Īt this point the starter is disengaged and the vehicle will need a constant supply of gasoline. Once you hit the starter it turns the engine slowly. When you turn the key to the on position, all three of these system engage and are ready for you to start your Passat. If you vehicle starts up, but then immediately quits, it may be getting all three at first, but something is clearly keeping it from getting all three consistently. Your Passat’s engine needs 3 things constantly and in the proper proportion to keep running. ![]() ![]() It is most likely caused by some type of issue with the electrical or fuel system. It can be very disconcerting if your Volkswagen Passat is starting and then dies.
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