P0456: Evaporative Emissions System Small Leak Detected

What does P0456 mean?

P0456 is a diagnostic trouble code indicating "Evaporative Emissions System Small Leak Detected". This code relates to your vehicle's evap system and should be diagnosed to determine the root cause. The severity level helps indicate how urgently this should be addressed.

Symptoms you may notice

• Check engine light (MIL) illuminated on dashboard
• Fuel smell near the vehicle
• Difficulty filling fuel tank

Common causes

• Faulty evap system component
• Wiring or connector issue in the related circuit
• Failed sensor providing incorrect readings
• Software/calibration issue requiring ECU update
• Related component causing secondary fault

What should you do?

This code sits in an engine peripheral, typically emissions or forced induction. It will not take braking or steering away, but it can put the car into limp mode, cost you fuel and fail a roadworthy. Book it in rather than clearing it and hoping.