I've run into this. I also replaced my actuator, to no effect - light stays on.
The more i've been reading, the more I'm thinking (and fearing) that the manifold flow valves themselves are not working. There's a return spring that either gives up, or the plastic of the intake manifold that holds the spring, breaks. Unfortunately, you need to replace the whole intake manifold in either case.
It may also be the sensor that picks up the manifold flow valve position, but I don't know if that's a replaceable part or not yet.
Chances are, though, your electrical system is fine. The damn manifold flappers are a very common issue for the GEMA engines...