How do i fix p1518 code on 1999 ford windstar?

No doghouse on a windstar. It's a cover over the engine that is removed from the passenger compartment. Aerostars had a dog house. There is a small link rod from a vacuum diaphragm to the intake runner. It is probably unhooked.

P1518 - Intake Manifold Runner Control Malfunction (Stuck Open) The IMRC system is monitored for failure during continuous, key ON engine OFF or key ON engine running self-test. The test fails when the signal on the monitor pin is less than an expected calibrated range at closed throttle.

• IMRC monitor signal circuit shorted to PWR GND or SIG RTN
• Damaged IMRC actuator
• Damaged PCM

An IMRCM PID reading approximately near 1 volt at closed throttle may indicate a fault
video's on youtube

P1518 - Intake Manifold Runner Control Malfunction (Stuck Open) The IMRC system is monitored for failure during continuous, key ON engine OFF or key ON engine running self-test. The test fails when the signal on the monitor pin is less than an expected calibrated range at closed throttle.

• IMRC monitor signal circuit shorted to PWR GND or SIG RTN
• Damaged IMRC actuator
• Damaged PCM

An IMRCM PID reading approximately near 1 volt at closed throttle may indicate a fault
It's part of the intake manifold . View P1518 on youtube .
2000 150 4 2L V6 Fault Code P1518 IMRC

its your intake manifold runner. its a silver box. they all go bad. ether a corroded chip bord or the bar falls off that controls it. If you hear a rattle sound coming from the dash its a barr that fell off if no sound then corrosion. ford wants 600 to fix this but you can do it yourself without bying a new one. ill try to post a link.

http://passionford.com/forum/ford-focus-st/400597-st170-fault-code-p1518.html

For error code P1518 troubleshooting,click the link below :----http://schematicsdiagram.blogspot.in/2012/03/obd-code-p1518-on-ford-windstar.html
--------This will help.Thanks.

This code means the intake manifold runner is stuck open either from a faulty actuator on the intake or the valves plates are gunked up unable to move,

Look at the coil pack, these are known to develop cracks, usually on the underside in the resin, you have to remove it to tell. It is much easier to reomve with the wiper cowl removed.

http://www.automotivehelper.com/topic551576.htm
Why did you replace the IAC?

P1518 Inlet Manifold Runner Control Stuck Open. Check to see if clips are broken. I would also get a haynes manual from your local parts store . Hope this helps

Just a suggestion. Take it to your local Advance Auto Parts store.They will give you a FREE diagnostics test. They can tell you the problem, cost, and code meaning. I hope you the best.