No need to freak out because this is a fairly minor issue that needs just a simple solution. Your car is perfectly in order.
To be able to resolve it, all you need to do is to understand something a little bit about your fuel system, computer, and the check engine light.
What Causes The Check Engine Light After Running Out of Gas?
Disrupted Fuel Pressure
Fuel pressure(air-to-fuel ratio) is an important part of a car’s engine operation. The engine requires a certain amount of it to operate normally. This allows it to run as efficiently as possible and have a longer lifespan.
Notably, the engine doesn’t always experience a constant fuel pressure level. In other words, the pressure level can be high or low, depending on the fuel level.
For example, it’s low when fuel is low and high when fuel is high. When the fuel runs out, the fuel pressure will also run out, totally disrupting the normal operation of the engine to an extent that it stalls.
If the fuel pressure level is lower than what’s recommended by the engine manufacturer, the ECM(the engine’s computer) becomes alarmed.
Consequently, it triggers the check engine light to warn you that something isn’t right with your engine so you can check it.
According to TI Automotive Aftermath, car engines require a fuel pressure of between 4 PSI(28 kPa) and 60 PSI(414 kPa), depending on the engine type and the fuel system it uses.
It further suggests that carbureted engines generally require lower fuel pressure compared to modern, high-performance, multipoint fuel-injected engines.
Takeaway: When you run out of fuel, similarly you run out of fuel pressure. Yet your engine requires a certain amount of fuel pressure to run efficiently.
The fuel pressure sensor serves to monitor your fuel pressure levels whenever the engine is running. If it detects that fuel pressure has been lost, it immediately signals the ECM.
In turn, the computer quickly triggers the check engine light. That’s why you’ll see the check engine light after running out of gas.
The check engine light could be either constant or blinking, depending on your car. To resolve it, you’ll need to restore your recommended fuel pressure level.
This you can do by refilling your gas tank. If the light doesn’t go away on its own, you’ll need to reset it, using one of the various methods available;
The Scan Tool Method: The Easiest and Fastest Method
Turn off all the gadgets and accessories in your car that use power.
- Connect the scan tool to the onboard diagnostic connector(OBD – II). Every car comes with one and it’s normally located under the steering wheel.
- Turn the ignition switch to the “ON” position.
- View the error codes displayed on the OBD-II by pressing the “READ” button.
- Clear the codes by pressing the “Erase” button. This will turn off the check engine light.
The Battery Disconnecting Method: A Traditional Method
For this step, you’ll require a wrench.
- Take out the positive and negative cables from your battery terminals, using the wrench.
- Drain the remaining power from your battery by holding the horn for about 60 seconds.
- Reconnect the battery after about 15 minutes by returning the cables.
- Start and stop the engine three times consecutively with about 2 seconds gap in each cycle. The check engine light should go away.
How To Prevent This Problem from Happening Again In the Future
Always avoid driving on low fuel. Always check your fuel driving range and top up your fuel accordingly before or once you start the journey.
Nearly all modern cars come with a fuel range feature that shows you approximately what distance your car can cover with the remaining fuel.
It’s normally located in the driver information center (DIC) found at the bottom of the instrument panel cluster.
Your engine requires a certain amount of fuel pressure to operate as efficiently as possible. The level of fuel in your tank will have a direct impact on it.
The fuller your fuel tank is, the better the pressure, and vice versa. If your car runs out of gas, the check engine light will occur because the fuel pressure sensor has made the computer think that something is wrong with your engine. Refilling your fuel tank and resetting the check engine light will help resolve it.