OBD-II Code
P1518
Severity
Not yet reviewed
Nobody on our side has assessed this code yet, so we are not going to guess at how serious it is.
Can you drive it
We cannot say
Treat it as unknown until a shop reads it with live data. If the check-engine light is FLASHING, stop driving as soon as it is safe to — that means an active misfire, whatever the code.
Indicative cost (USD)
$90–$480
From this code's diagnostic notes. Varies by vehicle, diagnosis, parts, and local labor. This is not a repair quote.
$90 (actuator only, DIY) to $480 (actuator + intake manifold clean + new gasket set, installed).
P1518 is a Ford-specific Intake Manifold Runner Control (IMRC) Stuck Open code — meaning the IMRC actuator (a small DC stepper or vacuum-operated motor on the intake manifold that opens and closes secondary runner butterflies for low-rpm tumble vs. high-rpm flow) is reporting via its position feedback that it's stuck in the open (high-rpm) position when the PCM commanded it closed.
How a shop works this
Work from evidence to part, not the other way round. A code names a circuit or a symptom; it does not name the part that failed.
Note every code that is set, not just this one.
Codes that appear together usually narrow the cause faster than any one of them read alone.
Read the freeze frame — the conditions the fault was recorded under.
Cold or warm, idle or load, road speed and engine speed. A fault that only appears cold is a different fault from one that only appears under load, even with the same code on the scanner.
Confirm the fault is current rather than history.
Clear the code and see whether it returns under those same conditions. A code that does not come back may have been logged during a repair, a flat battery, or a bad connection that has since been disturbed.
Then follow the diagnostic notes further down this page, in the order they are written.
They are written in the order a shop works this code, cheapest checks first. Where they name a component, inspect its wiring and connector before replacing it.
If the code comes back after a repair, the underlying fault is still there. That is the point to bring in a scanner with live data and freeze-frame, or a shop that has one.
Common symptoms
- Check engine light
Read the full diagnostic procedureP1518 is a Ford-specific Intake Manifold Runner Control (IMRC) Stuck Open code — meaning the IMRC actuator (a small DC stepper or vacuum-operated mot…
P1518 is a Ford-specific Intake Manifold Runner Control (IMRC) Stuck Open code — meaning the IMRC actuator (a small DC stepper or vacuum-operated motor on the intake manifold that opens and closes secondary runner butterflies for low-rpm tumble vs. high-rpm flow) is reporting via its position feedback that it's stuck in the open (high-rpm) position when the PCM commanded it closed. Engine symptoms are usually a flat torque curve below 3000 rpm and rough idle.
Cheapest-first ladder
- Visually inspect the IMRC actuator arm at the intake manifold — disconnect the linkage and move the butterflies by hand; if they're seized from carbon buildup, the actuator is fine and the manifold needs cleaning.
- Scan-tool live data on IMRC commanded position vs. actual feedback — should track within 5%; if feedback pin reads stuck at 0 V or 5 V regardless of command, the position-feedback potentiometer inside the actuator is dead.
- Ohm the stepper motor windings and check current draw with the PCM commanding cycle — Ford 3.0L Vulcan / Duratec spec is 0.3-1.5 A peak during a full open-to-closed sweep; under-current means an open winding, over-current means a binding mechanism.
- On vacuum-operated IMRC systems (older 2.5L/3.0L Taurus, early Escape), check the vacuum supply and the IMRC solenoid before condemning the actuator — a torn vacuum diaphragm or a stuck-vented solenoid mimics a stuck-open actuator. Don't replace the entire intake manifold for a $90 actuator before reading KAM for prior repair attempts and unauthorized-tune flags — some Livernois / SCT tunes for the 3.0L Duratec disable IMRC control entirely, which can leave the actuator parked open and set P1518 every drive cycle without any hardware fault.
Vehicle-specific patterns2002-2008 Ford Taurus / Mercury Sable 3.0L Vulcan is the canonical P1518 — the IMRC actuator is bolted to the front of the intake manifold and expose…
- 2002-2008Ford Taurus / Mercury Sable 3.0L Vulcan is the canonical P1518 — the IMRC actuator is bolted to the front of the intake manifold and exposed to engine bay heat, the stepper motor windings fail around 100-130k miles, and Ford had multiple service bulletins covering the failure.
- 2004-2007Ford Escape / Mercury Mariner 3.0L Duratec throws P1518 from the same IMRC actuator pattern.
- 2008-2012Ford Fusion / Lincoln MKZ 3.5L Duratec sees P1518 less frequently but when it occurs it's almost always carbon buildup on the IMRC butterfly shaft, not a dead actuator — clean the manifold instead of replacing parts.
- 2001-2004Ford Escape 3.0L early-build occasionally throws P1518 from a torn IMRC vacuum diaphragm on the vacuum-actuated variant.
Estimated repair$90 (actuator only, DIY) to $480 (actuator + intake manifold clean + new gasket set, installed).
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