P04AF

Symptoms

• Check Engine Light Is On
• Strong smell of gasoline when opening the hood or in the fuel tank area
• Deteriorating fuel economy
• Unstable idle
• Difficulty starting in hot weather (vapor pressure in the tank)
• Possible activation of the fuel tank safety valve

Causes

• Mechanical jamming of the purge valve solenoid
• Valve clogged with resinous deposits from the adsorber
• Broken valve return spring
• Corroded valve stem
• Valve icing in extreme cold (temporary cause)
• Deformation of the plastic valve body due to fuel exposure

How to Fix

1. Perform purge valve B activation test via scanner - check if mixture composition changes
2. Check the valve solenoid: when 12V is supplied directly, the valve should open with a characteristic click
3. Inspect the valve for resin deposits and body deformation
4. Check the hose from the adsorber to the valve for blockages
5. Try cleaning the valve with carburetor cleaner (if the body is not deformed)
6. Replace purge valve B (mechanical jamming most often requires replacement)
7. Check the condition of the carbon adsorber - replace if saturated
8. Reset codes and make sure the purge is normal during a test drive

Related codes

Error P04AF by Vehicle Brand