Question:

It seems the light comes on right before I fill up, and then it goes off again – why is that?

Answer:

We have addressed the topic of the check-engine light in the past, but not with such a narrow focus on this particular activity that might cause the light to illuminate. It’s true, we have seen situations in which the fuel is so low, the engine registers that it is running too “lean” (not enough gas in relation to the oxygen). Most likely, the fuel pump is having trouble picking up those dwindling volumes of gas at the bottom of the tank.

• Have your fuel filter checked to see if it needs to be replaced.
• Get your vehicle “scanned” to see if the computer code indicates a lean condition.
• Check to see whether your fuel gauge is working correctly – you might not have as much fuel as you think just prior to your regular fill-up.

You can also have your fuel pump performance evaluated. One thing to keep in mind – fuel cools the fuel pump, so if it’s not getting enough fuel, the pump gets overheated, affecting performance.

Bottom line: Yes, if you see a pattern in which the engine light comes on during periods that your tank is low, then turns off right after you fill it (and tighten the gas cap!), one of the above issues is probably going on.