Repair instructions
P1518 Code: Intake Manifold Runner Control (Stuck Open)
Summary
The P1518 code refers to an issue with the Intake Manifold Runner Control (IMRC) system, indicating that the powertrain control module (PCM) has identified a malfunction. This typically occurs when the IMRC valve is supposed to be closed but is detected as open. Common culprits include a malfunctioning IMRC actuator, wiring issues, or electrical connection faults. Symptoms often include a check engine light and a noticeable drop in engine performance.
What Does the P1518 Code Mean?
The P1518 diagnostic trouble code (DTC) specifically indicates that the IMRC valve is stuck in the open position. This code is common in Ford, Mercury, and Lincoln vehicles. The PCM triggers this code when it detects a discrepancy in the IMRC system, primarily when the valve is supposed to be closed but is still reading as open.
Understanding the IMRC
The IMRC system consists of two aluminum intake passages: one that remains open and another equipped with a butterfly valve that opens and closes as needed. The system relies on a motorized actuator and internal switches to relay real-time data about the valve’s position to the PCM. When the PCM identifies a fault—such as the valve being stuck open—it logs the P1518 code.
Common Causes of the P1518 Code
- Faulty IMRC actuator
- Open or shorted actuator wiring
- Electrical connection problems
- Malfunctioning Powertrain Control Module (PCM)
Common Symptoms of the P1518 Code
- Illuminated check engine light
- Reduced engine performance
Diagnosing the P1518 Code
Diagnosing a P1518 code can be complex and requires a solid understanding of your vehicle’s IMRC system. Since engine designs vary widely among manufacturers, familiarity with your specific model is crucial.
Fixing the P1518 Code
Repairing the P1518 code can be challenging, particularly for those without extensive automotive experience. If you’re not confident in your skills, it’s advisable to consult a qualified mechanic who specializes in IMRC-related issues.
For the DIY enthusiast, it’s essential to gather as much information as possible before attempting repairs. Utilize resources specific to your vehicle model to ensure a thorough understanding of the problem and proper repair procedures.
