The P0006 fault code, applicable to all car manufacturers, means that the fuel cut-off valve A control circuit is low.
The P0005 fault code, applicable to all car manufacturers, means “Fuel Cut-off Valve A Control Circuit/Open Circuit.”
The P0004 fault code applies to all car manufacturers and means the fuel quantity regulator control circuit is high.
Background knowledge: (In new cars where fuel injectors are widely used, fuel quantity regulators are rarely used)

