ODB Code P1538

The Check Engine light came on (1996 3.8 litre Windstar GL). AutoZone read it with handheld device and advised ODB Code P1538, which they say is intake manifold runner control stuck open left bank and intake manifold runner control stuck open right bank. My Texas inspection sticker just expired and inspector guys won't touch it until Check Engine light is out. Is there some way I can reset it (disconnect battery?)? Car runs just fine now. So what is an intake manifold runner control and what can I do about it?

I can't tell you exactly why the IMRC is there but both mine went bad on my 96 too. It's basically a little vacuum operated actuator that opens and closes a valve on the intake manifold. I think it opens the valve at wide open throttle (but I could have that backwards). After I replaced mine I had much better throttle response. The controller unit is a real cheap piece of crap but Ford is really proud of it - you'll understand when you see the price! There is no way to repair the thing and you obviously don't have a choice but to buy a pair of new units. I replaced mine at the same time as I did a intake manifold gasket replace so it was pretty straightforward having all that stuff off anyway - not sure if you'll be able to do it without taking the manifold off. So it may be easy, maybe not? You can check the IMRCs by disconnecting the other end of their vacuum lines and sucking on the end - if the thing doesn't move they are shot. If they do move you'll need to go back through the system and figure out what is causing the problem. The IMRCs are notorious for going bad anyway so that's probably the what's wrong.

Go to www.millenniumford.com and Ed in parts will help you out. They were half the price of my local dealer - It'll still hurt but $300 is better than $600.

Good luck
Robert

Hi
code 1538 is IMRC stuck open bank 2 which is the bank closest to the radiator and therefore the forward actuator. Think of the IMRC's somewhat like the secondaries on a carburetor. They only open at high RPM (2900). Unfortunately on the older models like ours, Ford built them to fail (absence of vacuum) open under the spring pressure of the actuator. In normal ops. vacuum pressure on the IMRC actuator pulls the internal valves closed until high RPM is sensed.

You will find these two buggers on the passenger side of the engine attached just off the end of the lower intake manifold. The forward one is just behind the alternator. I'll attach a link to a photo. But concentrate first on the forward one. Make sure the actuator arm is actually attached to the valve on the intake - the arms are held on by small plastic retainers that can fail. The next thing as was mentioned is: does the actuator respond to vacuum? In this case likely not. You could pull the vacuum line (on top) from the forward valve an plug it, start the van and observe if the rear actuator moves - the actuator arm should "suck in" pulling the valve closed at idle. If that works, you have isolated a leaking forward actuator and would have to replace it. I just received one from rockauto.com. They have an aftermarket Dorman valve for $71. Your front one is the LH valve in their catalog under engine/intake manifold runner control valve.

http://info.rockauto.com/RB/Detail2.html?http://www.dormanproducts.com/images/items/hwrap1/47097.jpg

To get past inspection you could go to Autozone, ask them to read AND erase the code which will clear the light. If you go directly to inspection it may stay off for a short while and may get you through that step. I say may as you would likely in this scenario have a bit of rough idle due to vacuum leakage, and may pop a lean fuel mixture code. If WA has a dyno test as part of the emissions (VA did) and they run it high RPM simulating street driving it may pop the code during the test. I just can't say positively.

Good luck. Welcome to the IMRC club. Everyone with a '96 joins it eventually.

how about wiring it close like others have done in the past? Clear the codes and run it for inspection that same time to avoid any issues. Quick fix at least till the inspection is done.

how about wiring it close like others have done in the past? Clear the codes and run it for inspection that same time to avoid any issues. Quick fix at least till the inspection is done.

You can give that a whirl, but I believe the position sensing is in the IMRC vacuum actuator, hence the electrical connection. As the arm would stay fully extended, eventually you will trip a stuck open code.

I tried both open and closed in less then 40 miles two codes came on I only had one before. anyway in NY my 98 Windstar has to travel 57 miles after codes have been erased. The light isn't on but the garage still says it won't pass with the pending codes.

The intake butterflies are probably gummed up and will require a partial tear-down to fix it.