P1518: Intake Manifold Runner Control Stuck Open
2 vehicles · 2 makes · $100-$600 repair
Most Reported On
P1518 is an OBD-II diagnostic trouble code meaning “Intake Manifold Runner Control Stuck Open.” This manufacturer-specific code (common on Ford, Lincoln, and Mercury) indicates the intake manifold runner control (IMRC) is stuck in the open position. The IMRC uses butterfly plates in the intake to change air-passage length and improve airflow across the rpm range; the computer commands them closed at lower rpm but here detects they remain open. When the system commands 'closed' but the monitor still reads 'open,' P1518 sets. The result is often weak low-end torque, rough idle, and reduced fuel economy. This code is most commonly reported on 1998-2000 Ford Contour, and 1999-2002 Mercury Cougar, with repair costs ranging from $100 to $600.
Common Causes
Typical Repair Cost
Based on 2 documented vehicle-specific issues. Actual cost depends on root cause and vehicle.
Diagnostic Tools
To diagnose P1518, you'll need an OBD-II scanner. Here are our recommendations at every price point.
ANCEL AD310 Classic OBD-II Scanner
by ANCEL
A simple, affordable code reader that reads and clears check engine codes. Great for quick diagnostics on any OBD-II vehicle (1996+).
- Read & clear engine codes
- View freeze frame data
- I/M readiness status
- No batteries or app needed
BlueDriver Pro Bluetooth Scanner
by BlueDriver
Bluetooth OBD-II scanner with a free companion app. Provides enhanced diagnostics, smog readiness, and repair reports sourced from a database of verified fixes.
- Enhanced diagnostics (ABS, SRS, transmission)
- Repair Reports with verified fixes
- Smog check readiness
- Free app (iOS & Android)
LAUNCH CRP123X OBD-II Scanner
by LAUNCH
A professional-grade handheld scanner that reads all four major systems (engine, transmission, ABS, SRS) with live data streaming and graphing.
- Engine, transmission, ABS, SRS diagnostics
- Live data stream & graphing
- AutoVIN for vehicle identification
- Free lifetime updates via Wi-Fi
Autel MaxiCOM MK808S Diagnostic Tool
by Autel
Shop-level diagnostic tablet with bi-directional control, active tests, and full system coverage. Ideal for serious DIYers and small shops.
- All-system diagnostics (25+ modules)
- Bi-directional control & active tests
- Oil reset, EPB, BMS, TPMS, injector coding
- 7-inch touchscreen with Android OS
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FAQ
What does P1518 mean?
P1518 stands for "Intake Manifold Runner Control Stuck Open." This manufacturer-specific code (common on Ford, Lincoln, and Mercury) indicates the intake manifold runner control (IMRC) is stuck in the open position. The IMRC uses butterfly plates in the intake to change air-passage length and improve airflow across the rpm range; the computer commands them closed at lower rpm but here detects they remain open. When the system commands 'closed' but the monitor still reads 'open,' P1518 sets. The result is often weak low-end torque, rough idle, and reduced fuel economy.
What are the most common causes of P1518?
The most common causes of P1518 are: Stuck or broken IMRC actuator, Seized or carbon-fouled runner butterfly plates, Broken or disconnected IMRC linkage, Open or shorted actuator wiring, Corroded or loose IMRC connector, Weak or broken return spring, Faulty PCM/ECM (rare). The specific cause varies by vehicle.
How much does it cost to fix P1518?
Repair costs for P1518 range from $100 to $600, depending on the vehicle and root cause.
Which vehicles are affected by P1518?
Au7o has documented P1518 across 2 vehicle models from 2 manufacturers: Ford, Mercury.
Sources (7)
- ForumIntake Manifold Runner Control Stuck Closed | New Cougar Forum
- Forum2002 cougar imcr | Mercury Cougar Owners
- ForumSOLVED: How do I fix imrc on the 2002 mercury cougar p1519 - Fixya
- ForumLooking for intake manifold runner control please and thank you | New Cougar Forum
- Forumcode P1519 Inlet manifold runner control malfunction (Stuck Closed) | New Cougar Forum
- ForumIMRC Stuck Open? P1518 | New Cougar Forum
- articleP1518 – Intake Manifold Runner Control Stuck Open (Ford, Lincoln, Mercury) – TroubleCodes.net
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.