Dunno about VW but some of these runner control valve things are apparently vacuum operated, so if your exhaust is clogged, your intake manifold vacuum might not give enough suck to move it, though it won't really be stuck as such.

If "stuck" actually appears in the definition of the code, then it is sloppily written and misleading.

Edited by edlithgow on 18/11/2020 at 04:24

....massive loss of power and the revs doesn’t go over 2500-3000 RPM(feels like something’s blocked)..........fault codes came up was P2004 intake manifold stuck open (bank1) and P000A camshaft position “A” timing; slow response...... So I took the it to the mechanics and had the intake manifold changed. But the car is still the same ....

I wonder how often the unsuspecting motorist is fleeced for an incorrect diagnosis and subsequent useless treatment? This example is the automotive equivalent of treating constipation by dilating the gullet.

Is it?

I don't have an "Intake manifold runner control " to stick (POOR, POOR ME) but I assume its something to do with variable intake geometry to actively tune the (Helmholtz) resonance in the runner.

I'd imagine the runner valve thingy position will be sensed using some kind of potentiometer thingy. If the ECM (or whatever its being called this week) says its stuck when it isn't, just because the exhaust is clogged, which yáll seem to be saying, then OBDII is a bit of a Delphic Disaster.

Quite glad I don't have it now.

Getting closer to things I sort of understand, you can tell if your exhaust is clogged using a vacuum/pressure gauge. I improvised an adapter for it between two exhaust sections, but I believe you can also use the oxygen sensor port, if you have one and can get the sensor out of it.

Its alleged you can also diagnose it using intake manifold pressure measurements, but I couldn't make any sense out of that and gave it up as a counter-intuitive bad job.

You can also tell if you have a blocked exhaust (and possibly unblock it) by separating the rear half of your exhaust system and sticking a garden hose in the back, though I havn't tried this with a catalyst

Edited by edlithgow on 17/11/2020 at 12:29

....massive loss of power and the revs doesn’t go over 2500-3000 RPM(feels like something’s blocked)..........fault codes came up was P2004 intake manifold stuck open (bank1) and P000A camshaft position “A” timing; slow response...... So I took the it to the mechanics and had the intake manifold changed. But the car is still the same ....

I wonder how often the unsuspecting motorist is fleeced for an incorrect diagnosis and subsequent useless treatment?

Dunno, probably pretty often, but I'd think the unsuspecting motorist often gets fleeced for a correct diagnosis and useful treatment too, because the system is set up that way.

Lets say this code WAS generated by a fault in the runner control valve (I accept it probably wasn't in this case).

Say the vacuum line was split where it joins the valve. This could probably be detected by a visual examination and fixed by:-

(a) a quick snip of the scissors, shortening the hose line a bit, at zero cost.

(b) Swapping out the whole intake manifold (which, if its like the one linked below, is a big piece of plastic with officially no replacable parts) at considerable cost.

Either would fix the problem, but I'd bet option (b) is the industry favorite.

Being fleeced pretty much goes with the "unsuspecting motorist" territory. That s why they call them "unsuspecting motorists"

www.youtube.com/watch?v=yvfVUkuPY0k