Obtained fault codes P1512 and P1538

Had the CEL go on/off for some time on my Windstar 3.8 ’98 but it is now on permanently. Took it in and got P1512 and P1538 - at the same time. The local Ford dealer wants to replace both the intake manifold runner control (IMRC) at $1100, total…….

Knew nothing about this 2 days ago but have I’ve read everything on this site about the IMRC issues. Thanks to everyone for great info.

I’ve done the test where you find out which one is leaking by pulling the vacuum line from one of the controllers and plugging the end with your finger. The Bank#2 IMRC appears to be leaking. So far so good with P1538. But the P1512 code (bank #1 stuck closed) is a mystery to me - as it is stuck open due the bank#2 leak. Is this a related issue? Should I just replace the front IMRC? Or is this a separate (sensor/electrical) issue? Help... Thank in advance!

I don't know why you would get a "stuck closed" indication.....
Maybe you can see if you can move them by hand.
The should be open when the engine is not running, and the vaccum pulls them closed.
The PCM sends a signal to a vaccum regulator, that is on the back side of the upper intake manifold that turns off the vaccum to the actuators.

They carry the actuators at www.rockauto.com
They had them listed under "choke pull off", which is not what they are.....but they are the actuators.
I think they had the same part listed under a different name....they sometimes do that....but the "choke pull off" was strange enough for me to remember.

Thanks for the RockAuto hint - and how to find the part!

Both front and rear IMRC can be moved (all the way) by hand.

When I block the front vacuum line the rear will close just fine. This why I expect that the P1538 is due to a leak in the front IMRC.

The cacth is that the leak in the front IMRC is laving the rear IMRC stuck open, while the P1512 code is the rear IMRC reporting stuck closed...In other words, due to a leak both IMRCs are stuck open but one is reporting the opposite position.

...New to this issue, I guess that I was hoping that I had missed something and thus missed an obvious relationship between the two (related) codes.

Well, maybe the actuator is stuck in the "closed" position...or even that part being bad also...... The actuator assembly has the diaphram part....that moves the linkage, and thus the intake runner. The other part of the actuator is the electrical part that senses the position of the actuator, which is supposed to correspond to the position of the runner.
So, I would order a new actuator assembly, and see if that clears up the codes.