You’re A Mechanic If You Can Pass This Essential Car Maintenance Quiz

If the fuel filler cap is not screwed in, what can happen?

Retry Correct Incorrect If the fuel filler cap is not properly screwed in, the pressure in the fuel system can get disturbed, and that leads to the ‘check engine light’ being shown in the dash.

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Scott J. Ferrell/Congressional Quarterly via Getty Images

Scott J. Ferrell/Congressional Quarterly via Getty Images

If the fuel filler cap is not screwed in, what can happen?

• Fuel will evaporate faster
• The fuel tank might blow up
• The fuel pump can fail
• The check engine light might turn on