Volkswagen: Fuel System Error code Golf4 2.0, mass flow meter, fuel pressure regulator

Question
Recently I replaced the air mass flow meter on my Golf4 2.0L after diagosed by the agents as faulty. Since I replaced the air mass meter the car has been running well, however with cold starting the choke does not come on and the vehicle idles as per normal running conditions. The diagnostic report indicates a 40AC fault and fuel bank mixture too rich, this indicates that the Purge control valve may be faulty. It did not do this before the mass meter was replaced and I wonder if it warrants replacing this valve as it is a costly exersize and will this worsen over time? Please advise.

Answer
Hey Mark,

If you are getting that 40AC code,  either the fuel pressure regulator has a proglem or the purge valve may be at fault.  I'd first check to make sure that you have a good seal everywhere, and all of the wires and hoses are on tight.

If after a system clear, this error still comes on, most likely you are going to have to replace the pressure regulator or the purge valve.